Ally Support
Overview

From the FEHereos In-game news. Original post here.

You can deepen bonds between Heroes through Ally Support. Support can be set for pairs of Heroes in the Advanced Growth menu. Deploy pairs of Heroes into a battle with enemies level 35 or higher to build their Support Rank from C to S.

When two Heroes who support each other are nearby during battle, they will receive a stat boost. Heroes will receive different boost effects depending on whether they are adjacent to each other or separated by one space.

You can choose to honor the relationships between Heroes from throughout the series or build relationships between Heroes that work well together on the battlefield. It's your choice!

  • Ally Support pairings can be changed at will. However, if you build the Support Rank between two Heroes up and then switch one of the Heroes to another pairing, the Support Rank for the initial pair will be reset to C.
  • You can create multiple Ally Support pairs. However, each Hero can have only one active support pairing at a time.
  • Multiple identical versions of a Hero cannot each have separate support pairings.
Notes
  • Identical heroes cannot support each other.
  • All characters can be supported, there are no restrictions.
  • Support rank increases only when battling enemies of level 35 or higher.
  • Enemies in arena don't benefit from support perks
Ally Support Perks
Support Ranks Boost (adjacent) Boost (one space away)
C RES +2 RES +1
B DEF/RES +2 DEF/RES +1
A SPD/DEF/RES +2 SPD/DEF/RES +1
S ATK/SPD/DEF/RES +2 ATK/SPD/DEF/RES +1
User Submitted Support Teams
Main Hero Supporting Hero
Canas Saias
Explanation by SapphireSea
What better way to aid a low tier unit than with a quad-ploy user? As long as the enemy doesn't carry Harsh Command, Sacrifice, Restore, or anything related, Saias can set up a ploy so Canas can handle the enemy a little better. In addition, if Canas keeps his native owl tome, it'll be more than just support bonuses he'll get from his partner should they be next to each other.
Main Hero Supporting Hero
Legendary Ike Marth
Explanation by MercMetal
Legendary Ike with Warding breath & Quick Riposte 3 is best combo for Radiant Aether which has 4 CD as it require enemy to initiate attack against Ike which he can counter with two hits, last hit having his special activated.

Only problem is Ike mid 30 speed make him prone to being doubled by follow-up attack, especially speedy enemy with 2 CD Special.

Marth's Falchion upgrade in weapon refinery 'Grants Atk/Spd/Def/Res+2 to allies within 2 spaces during combat.' Combine with C Skill 'Spur speed 3' with Seal 'Spur speed 3' and finally S rank Ally bonus which all together grant 12 speed. This boost Ike's speed from 30 to 42 along with other stats from Falchion & Ally bonus. This is enough to support ike to denied enemy who relied on follow-up (unless they have 47 speed) which in turn prevent from being KO by 2CD special, as long Marth is adjacent to Ike.

A demonstration of Spur Speed & Drive speed in full effect for L Ike against Legendary Lucina on infernal difficulty
https://www.youtube.com/watch?v=az8_cOuNcb8
Main Hero Supporting Hero
Summer Leo Takumi
Explanation by Marble
No Proper Clothes Husband + Bangin Husband
Main Hero Supporting Hero
Summer Robin (F) Arvis
Explanation by FEHPlayer
Arvis heals S!Robin whenever she uses her Fury effect weapon. S!Robin has good stats all around, making Arvis' debuffs useful to help her take out an enemy. If S!Robin faces off against green units, Arvis is there to take them out. Also, S!Robin can't really go to the beach if it's not hot and sunny outside, so there's Arvis to go burn things down, so there's always a reason to go to the beach.
Main Hero Supporting Hero
Tiki (Adult) Legendary Ephraim
Explanation by nathanA
Tiki sits and tanks while Ephraim goes and takes out the enemies. They are a really good tempest trials pair
Main Hero Supporting Hero
Sothe Gunnthrá
Explanation by Jasagra
The synergy between their weapons is brutal. Sothe can debuff all enemies if they're gathered and buff all his companions as well. After that Gunnthrá can oblitarete any enemy with the buffs and debuffs but mainly with her tome. The Nifl Princess gets a gap of 8 dmg (+4 atk and -4 res) and a bonus +16 damage. Equip Sothe with double Savage Blow 3 and with a dancer they can clear almost any map by themselves.
Main Hero Supporting Hero
Myrrh Ninian
Explanation by MapleSenpai
Simple. Dragons

Ninian provides Fortify Dragons buff to Myrrh, further increasing her DEF/RES by 6, allowing Myrrh to proc her weapon "breaker" passive against enemies with DEF up to 37 if she's neutral DEF, or up to 40 if she has DEF boon. Myrrh's RES also increases from a 31 (neutral) to a 37 (buffed). Ninian being a dancer also allows Myrrh to be able to ORKO 2 units in one turn, if not KO a unit Myrrh cannot ORKO. Myrrh is already a great unit by herself, but with Ninian she is able to reach further heights, even allowing her to fight against speedy red units.

Ninian also benefits from Myrrh, by not only having the color advantage against blue units, but Myrrh can also check against green units as she has amazing mixed defensive stats. Hone Dragons is another skill that should be taken account for here. With Ninian having a low base ATK of 24 and a mediocre SPD of 33, Hone Dragons is able to boost her ATK to 30 and SPD to 39, enabling her to be able to pick a fight against some red units and avoid most fast units in the game. If also desired, give Myrrh a guidance seal and Ninian can move around freely the surrounding areas around Myrrh.

Myrrh and Ninian is, if not, the best pair of units to support each other.
Main Hero Supporting Hero
Myrrh Ninian
Explanation by Anonymous
Simple. Dragons

Ninian provides Fortify Dragons buff to Myrrh, further increasing her DEF/RES by 6, allowing Myrrh to proc her weapon "breaker" passive against enemies with DEF up to 37 if she's neutral DEF, or up to 40 if she has DEF boon. Myrrh's RES also increases from a 31 (neutral) to a 37 (buffed). Ninian being a dancer also allows Myrrh to be able to ORKO 2 units in one turn, if not KO a unit Myrrh cannot ORKO. Myrrh is already a great unit by herself, but with Ninian she is able to reach further heights, even allowing her to fight against speedy red units.

Ninian also benefits from Myrrh, by not only having the color advantage against blue units, but Myrrh can also check against green units as she has amazing mixed defensive stats. Hone Dragons is another skill that should be taken account for here. With Ninian having a low base ATK of 24 and a mediocre SPD of 33, Hone Dragons is able to boost her ATK to 30 and SPD to 39, enabling her to be able to pick a fight against some red units and avoid most fast units in the game. If also desired, give Myrrh a guidance seal and Ninian can move around freely the surrounding areas around Myrrh.

Myrrh and Ninian is, if not, the best pair of units to support each other.
Main Hero Supporting Hero
Arvis Fjorm
Explanation by Shishio
They're my go to team for just about every battle. Both are strong units. Arvis can hit far targets and Fjorm takes out everyone else while taking very little damage. I love them.
Main Hero Supporting Hero
Selena Ephraim
Explanation by KevTon13
It’s not that I think they’re perfect for each other. I only did this because Ephraim being able to buff up all stats is a blessing for Selena. Ephraim’s buffs are the reason on why Selena looks enhanced, and with ally support buffs, Selena will look even more enhanced.
Main Hero Supporting Hero
Eirika Ephraim
Explanation by RinkahWhere
Memes aside, this pairing is really good. The two buff each other with +4 attack every turn using their weapons and Eirika deals with green mages while Ephraim clears the field. If you desire a support that follows canon while doing work in-game, you should give this a try.

Truly, wincest is best.
Main Hero Supporting Hero
Myrrh New Year Camilla
Explanation by PinkPower
NY! Camilla can use the following set to best support Myrrh:
Kadomasu+ (+Spd, +Def or +Atk), Reciprocal Aid/Reposition, Bonfire, Fury, Desperation, Ward Fliers, Drive Def 2 Seal

Myrrh can run a Flier Emblem set:
Great Flame, Reposition, Bonfire, Distant Counter, Quick Riposte, Goad Fliers, Iote's Shield Seal

With this set and Ally support B or higher, NY!Camilla gives Myrrh +10 Def and +7 Res from one space away which helps greatly with Great Flame's effect allowing Myrrh to avoid doubles and easily kill mages with Distant Counter, plus being a spur buff it can't be Panic Ploy'd.

Reciprocal Aid allows NY!Camilla to heal Myrrh back into QR range and get herself in Desperation range which has good synergy but Reposition is always a solid choice on fliers too.

To round off the duo, Myrrh can run Goad Fliers in her C slot to give NY!Camilla +5 Atk/Spd from one space away which helps her offenses greatly.
Main Hero Supporting Hero
Winter Chrom Robin (M)
Explanation by eirika.sieglinde
for one theyre a nice ship, and in gameplay robin can take care of any red or colorless that might be annoying poor chrom and chrom tanks everything except maybe red mages
Main Hero Supporting Hero
Brave Ike Fjorm
Explanation by Zanger
This synergy is really good! B!Ike takes on the blue and green melees that Fjorm has trouble with and Fjorm take care of red mage,blue mage, red swords, red and blue dragons with the proper build.
Main Hero Supporting Hero
Winter Chrom Winter Robin
Explanation by championofdogs
These winter boys work well together. Robin gives Chrom the movement he needs, Chrom takes all the mage hits.
Main Hero Supporting Hero
Clive Mathilda
Explanation by HopeSoSure
Canon support in Gaiden and SoV, work very well in mid budget horse team.
Both Unit can patch up their each other weakness fairly easily. Clive excel at high attack, HP, and defence, Mathilda excel at high speed and high resistance synergise very well for a team defensive playstyle.
Clive can serve a good frontline attacker with Brave lance+ and some physical tank, while Mathilda can be a bait for mages from backline thanks to her Cancel Affinity and good spd to avoid double attack.
However, this combination can be very vulnerable against colorless bow and dagger unit due to Clive's low spd and Mathilda's low atk. Armor unit is also very scary to fight in enemy phrase since most of slow armored unit have Brave weapon can have trouble taking down, due to both unit are lance thus can have huge limitation with Rienhardt for a horse team. So dont forget to bring some fellow Ranged Horse or some red sword to counter some devestated situation in a horse team.
Main Hero Supporting Hero
Ayra Brave Lucina
Explanation by parse
Super charge Ayra with even more speed.
Brave Lucina (Geirskogul, Drive Spd, S Seal with Spur Spd or Hone Spd)
Main Hero Supporting Hero
Sigurd Cecilia
Explanation by SigurdTheGr8
Give both of them Hone Cavalry, Sigurd double Close Defense to tank all melee units, Cecilia Fortify Defense and keep rally res to help Sigurd survive all mages. If faced with a blue that Sigurd can't handle, Cecilia can ko it and Sigurd repositions her to safety.
Main Hero Supporting Hero
Sonya Arvis
Explanation by MrWilo99
Arvis can apply massive debuffs to the enemy units due to his legendary tome and his c skill. This can help Sonya not only attack with heavy damage, but also take less damage due to the -4 attack from Arvis' ploys.
Main Hero Supporting Hero
Black Knight Hector
Explanation by BlackReinhardt
Our boy Hector does a lot for the Black Knight, as he lures in blues and turns the BK into an offensive powerhouse with Goad Armor. In return, the BK supplies Ward Armor, helping Hector lure in units like Reinhardt more effectively.
Main Hero Supporting Hero
Tailtiu Performing Azura
Explanation by Confucius Rex
Blade tome the enemy to hell.
Main Hero Supporting Hero
Marth Caeda
Explanation by MrAtkins45
Uh... The ORIGINAL OTP!
Main Hero Supporting Hero
Robin (M) Minerva
Explanation by Wobbleleez
Running the classic raven tome, triangle adept, and sword/bow breaker Robin can cover for a lot of weaknesses Minerva has, couple this with the new guidance seal and fury on a bulkier Minerva build and they can do very well together
Main Hero Supporting Hero
Xander Cecilia
Explanation by SapphireSea
Cecilia is there to cover any blues that threaten Xander, especially magic users. Both run Fortify Cavalry as well, giving each other some more defenses.
Main Hero Supporting Hero
Linde Eirika
Explanation by Ouch Rude
Linde with Blárblade+. Eirika with Hone speed 3, Fortify Defense 3 sacred seal, and rally res. With every stat buffed and running fury and desperation, there is nearly nothing that can stop Linde. What can't is physical green units or Julia, which Eirika takes care of.
Main Hero Supporting Hero
Lyn Arvis
Explanation by Fantaman
These two are my most effective supports. Arvis with fury may only reach 34 speed, and my plus attack Lyn is still pretty frail and unable to survive many things. However, together they are essentially one great red duo. Arvis is the heavy hitter, tanking magic very well and dishing out hefty damage and spur speed from Lyn as well as the ally support shoots him to 40 speed. When he's not facing a great opponent, that's where Ploys and Lyn comes in. Lower attack, speed, and defense essentially makes opponent perfect for being killed by Lyn. Plus, Brash Assault and Galeforce allow her extra mobility as well as a way to insure a kill. The debuffing nuke and the agile swordwoman are just the perfect compements for each other.
Main Hero Supporting Hero
Arvis Deirdre
Explanation by Fudgenuggets
Yeah
Main Hero Supporting Hero
Ayra Eirika
Explanation by TheSeunger
Mainly because they share the same artist who drew them. Not really a serious pair, just something they have in common.
Main Hero Supporting Hero
Sigurd Deirdre
Explanation by serra
OTP
Main Hero Supporting Hero
Sigurd Arvis
Explanation by Socks
THEY ARE HOT TOGETHER
Main Hero Supporting Hero
Ryoma Tana
Explanation by Omnivye24
They both beat what each other cannot. Give Ryoma BowBreaker for pesky archers and Tana hit and run to tag team some enemies. I solo'd Ninian and Hawkye with these two. Also a powerful and charismatic prince deserves a princess that can hold her own. He can ride her pony any day.
Main Hero Supporting Hero
Alm Celica
Explanation by .logicalpoptarts.
No explanation because spoilers ¯\_(ツ)_/¯
Main Hero Supporting Hero
Brave Ike Effie
Explanation by Nezyrael
A great tank team that also has sound mobility with Pivot on Effie and Reposition on Ike
Main Hero Supporting Hero
Takumi Lucina
Explanation by Icarus
Run a CC Takumi build with Vantage 3. Give Lucina LnD 3 with Desperation 3 as well as Ardent Sacrifice. Enjoy infinite Desperation and Vantage.
Main Hero Supporting Hero
Narcian Roy
Explanation by Trowa
They further help each other remove specific colors.
Main Hero Supporting Hero
Brave Lucina Summer Elise
Explanation by MilodicMellodi
This is my best pairing I currently have for my best team. They don't really directly support each other with their skills, but the team is mostly close-knit and they're on multiple teams together so the pairing is good enough.
My Lance!Lucina has Rec. Aid, Sol, and Steady Breath, and Summer!Elise has Gronnblade+, Blazing Wind, and Heavy Blade 3. With Innes and Roy as the other two on my main team, it's strong and balanced enough that it's gotten me through most of the Arena itself.
Main Hero Supporting Hero
Hector Azama
Explanation by Jill Pill
give Hector Reciprocal Aid and the Deflect Magic seal

give Azama (-ATK +SPD) Pain/Panic/Slow, Martyr, Speed +3, Live to Serve, Threaten ATK, and the Distant DEF seal

give both of them Miracle

use Reciprocal Aid and Martyr whenever Hector's HP is lower than Azama's

enjoy being incredibly difficult to kill
Main Hero Supporting Hero
Roy Maria
Explanation by kato minari
This is a cute team I made the healer mage and the brave lion.
Main Hero Supporting Hero
Clarisse Performing Inigo
Explanation by sanicek
After inheritance this duo can tackle basically anything. Inigo with classic raven, TA, bowbreaker build takes care of Rein, Lyn and other blue or colorless units, he is master baiter. Firesweep Clarisse with drawback can kill or kite anything on ally phase and with poison strike/savage blow take care of even armor cubes and other bulky threats.
Works with any Firesweep archer, ie Bride Cord as well.
Main Hero Supporting Hero
Hector Delthea
Explanation by sisaac_nouise
+11 Attack to Hector
'nuff said
Main Hero Supporting Hero
Performing Shigure Performing Azura
Explanation by prince_piplup17
Neither of these units are that great when they're by themselves, BUT by letting them have an S support bond with each other, and if you give Shigure Life and Death, altogether, Shigure's attack will be about 49-50. Since Performing Azura's axe gives a unit Atk/Spd/Def/Res+3, Shigure's attack stat will then be 53, and he will have enough speed to double attack most units.
Main Hero Supporting Hero
Xander Reinhardt
Explanation by BigKnockOut
So I run the Cavalry Team metagame (Xander, Rein, Cecilia, and Brave Lyn), and Rein is almost always the one who engages and nukes immediately a powerful enemy unit. I always have Xander Reposition Rein out of combat to protect him from physical retaliation, so having the two paired up was a natural idea because they always were next to each other, or nearby, anyway.
Main Hero Supporting Hero
Reinhardt Brave Lyn
Explanation by simsims22
If you're running a cavalry team, why not support the two biggest nukes together? For maximum effectiveness throw Goad Cavalry on Rein and Hone/Fortify/Ward/Goad on Lyn.
Main Hero Supporting Hero
Olwen Camus
Explanation by ZeroTheThao
For a cavalry build, Olwen can be significantly stronger with Camus, due to goad cavalry. She can be boosted by the support stat, which make it 6+ attack, and if you have a death blow or swift sparrow build, it will dramatically make Olwen stronger.
Main Hero Supporting Hero
Kagero Brave Lucina
Explanation by Sain_For_Heroes
Brave lucina buffs kagero's speed by a whopping 8 and atk by 5 when next to her, allowing kagero to one-shot more units and double more units as well. Brave lucina can also be used as the main hero, because the +2 in speed and def helps with tanking alot.
Main Hero Supporting Hero
Jaffar Ninian
Explanation by VicariousXIV
Jaffar isn't the strongest of units on his own, but give him Desperation, Fury, the summoner support, and have a tanky(ish) dancer to not only block other melee units but to give him a second action? He will literally kill everything in the game that doesn't have vantage and a high attack. Not even TA-Raven units can survive him without vantage.
Main Hero Supporting Hero
Innes Boey
Explanation by some1random
Nidhogg Innes and CC Gronowl Boey. If they stand next to each other both their stats will be multiplied by 2 through their weapon effects + the support pair buffs + spur def/res all of which will stack with each other effectively turning them into magical and physical tanks respectively. For this pair, positioning is super important.

Thrown in Eirika w/fortify res seal for quad buffs (assuming she has rally res for an assit skill) and Lancina with spur def seal (can go on the other two if preferred) for more spur buff stacking and you effectively turning them both into walls and nukes. Just be careful with panic ploys and where Eirika is placed. Also as said before positioning is very important, if using these two units along side Innes and Boey.

The duos (Eirika and Lancina support) also work pretty well in the current meta as well with Boey (w/bowbreaker) meant to counter B! Lyn and Innes meant to counter Reinhardt.

As for glaring weakness this duo is very susceptible to sword units especially the ones with DC. To help fix this just bring strong blue units like Lancina or units with sword breaker.
Main Hero Supporting Hero
Sheena Linde
Explanation by Lunar Fang
Wellll, BoL 3 and BoL seal gives 15 hp and also her stat spread including Summoner support is 50/42/26/48/37 making her nearly impossible to kill and can even tank some red mages :D and ez heals with linde and just kill all those pesky red units
Main Hero Supporting Hero
Brave Lucina Masked Marth
Explanation by Dr Mandom
¯\_(ツ)_/¯ Why not.
Main Hero Supporting Hero
Hector Brave Lucina
Explanation by lolroflpie
Do you love our blue haired husbando as much as I do? Do you have a brave Lucina taking up space? Slap these bad boys together and get ready for god to become more godly. Summoner support on hector improves his hp and defenses, and support with lucina serves as a soft fury. add on the ability to grant hector +6 attack and +3 speed and cover all his bad red unit matchups and this bad boy will devour anything without a ruby sword+ or raorblade+
Main Hero Supporting Hero
Azura Wrys
Explanation by Garunixreborn
What happens when you dance on a healer? Simple. You make healers actually GOOD.
Main Hero Supporting Hero
Effie Hector
Explanation by Garunixreborn
Hector and Effie are the two best knight units in the game, and both are really tanky. Hector with pivot will always stay near Effie and she can protect him from strong red units with her brave lance+, while hector helps against strong green units. Hector's Goad armor also has perfect synergy with this, making Effie's wary fighter more effective and thus, making them harder to kill.
Main Hero Supporting Hero
Ryoma Azura
Explanation by Hector Emblem
These two have a pretty cool relationship in Fates, and also work well together on the battlefield. Azura can buff a neutral-speed Fury Ryoma's speed to 40 and his attack, with Hone Atk, to 59. With the support bonuses and a Hone Atk, a neutral Fury Ryoma can gain a stat spread of 41/59/40/32/26, which is pretty ridiculous.
Main Hero Supporting Hero
Sheena Gwendolyn
Explanation by Steakbrine
This is my best support:
-Can give each other armor bonus.
-Gwendolyn with +6 Def/Res from Sheena is a great wall, even more with Renewal.
-Sheena can use Reciprocal Aid in order to take Gwen's life if necessary and it will not be a problem because of Gwen's Renewal.
-Gwen can use Swap on Sheena in order to protect her against red enemies or receive protection from green enemies.
Main Hero Supporting Hero
Hector Brave Lyn
Explanation by aceofmews
Pivoting hector using lyn makes him a faster mover, which also makes things die faster in less turns , and with max support and spur attack 2 gives her 5 more damage per attack. Plus right this is the closest I can get to the ship in the game right now.
Main Hero Supporting Hero
Spring Camilla Camilla
Explanation by NyxTheWitch
Waifu + Waifu
Main Hero Supporting Hero
Brave Ike Ike
Explanation by Mallozzi
We like Ike, we like Ike!
Main Hero Supporting Hero
Lucina Robin (M)
Explanation by CanADieNxFurY
My most-used powerhouses, and the first two 5-Star units I ever got to lvl 40.
Main Hero Supporting Hero
Robin (M) Chrom
Explanation by egglord
the only pairing we truly need
Main Hero Supporting Hero
Brave Lyn Reinhardt
Explanation by pol
With Rein's native goad cavalry, lyn gets 6 points to speed and attack which can further stack my her being my personal support and hone cavalry. When all's said and done, she has 48 and 59 attack on initiation with swift sparrow and a Brave Bow+, making her one of the best offensive units out there, losing 0 matchups and winning against 165 of the 168 vanilla heroes in the game.
Main Hero Supporting Hero
Kagero Brave Lucina
Explanation by HeiTCB16
Should be pretty self explanatory. Kagero is broken already, and assuming you keep Lucina's special lance and Drive Speed (not sure why you would change them in the first place), you're giving Kagero a +5 ATK/ +8 SPD boost by just placing Lucina next to her. This lets her pretty much ORKO any unit that isn't extremely bulky
Main Hero Supporting Hero
Brave Lucina Eirika
Explanation by Gray Person
Now this is a bit of a tough sell considering both units are used to buff other team mates. Together however they practically push each other to pretty high limits with Eirika allowing Brave Lucina to be even more flexible with whatever set up she has with Eirika honing more attack and other stats depending on what you give her and allow Eirika to dominate on other red and green units practically guaranteeing a lot of ORKO's if Triangle Adept is being used even with just +3 to her generally low attack. The repercussion is that both support characters end up supporting themselves more than other team mates but if you can find a complimentary support group then this should work more times than not.
Main Hero Supporting Hero
Bridal Cordelia Azura
Explanation by Gray Person
Any dancer paired up with Bridal Cordelia is generally a solid way to use the character and this can be even furthered with Bridal Cordelia having Escape Route active and whatever dancer you have with Wings of Mercy. This basically means Bridal Cordelia can move anywhere (near her other team mates) on the field and the dancer can still keep following her all the while Bride Cordelia for the most part barely has to move too far away from the dancer to benefit from the support boosts. This also is extremely helpful if using a Brave Bow to get Bridal Cordelia to get more quad hits in. Heck if you have a +spd Bridal Cordelia and they have the support bonus, that basically makes her reach 40 speed which coupled with a hone or spur speed can gaurentee doubles over characters that are set up to reach over that speed.
Main Hero Supporting Hero
Jagen Nino
Explanation by Lunala
Best team ever lol
Main Hero Supporting Hero
Summer Corrin (F) Eirika
Explanation by Valaga
Give corrin bladetome and pair her with 1 complete set of buff from eirika. You'll get a nice pair of waifus and b(r)east at the same time.
Main Hero Supporting Hero
Boey Mae
Explanation by trickstars
Get them near each others and it's guaranteed +4 to all stats
Main Hero Supporting Hero
Ike Soren
Explanation by KhaosDSF165
There best friend in PoR and RD plus there range attackers
Main Hero Supporting Hero
Corrin (F) Summer Corrin (F)
Explanation by IkeFanboy
waifu yourself!
Main Hero Supporting Hero
Nino Ephraim
Explanation by Ruu
Ephraim with his Lance gives Nino Plus 4 Atk and with Hone Speed 3 and Rally Spd and Atk can make her hit hard
Main Hero Supporting Hero
Innes Brave Lucina
Explanation by ShadowMage00
This pair is extremely effective and takes advantage of the owl effect innes's bow has. When next to lucina, innes gains +5 atk, +8 spd, +4 def and +4 res. These boosts allow innes to take care of any mages that threaten lucina while she is able to tank blue and red units and Together they can take care of greens as long as it isn't an emerald axe wielder. If innes has summoner support it is an additional +2 in every stat and 5 hp which adds to his survivability
Main Hero Supporting Hero
Summer Elise Elise
Explanation by Haroff
Elise is her own best friend
Main Hero Supporting Hero
Henry Summer Corrin (F)
Explanation by Magenta Flame
I ship it.
Main Hero Supporting Hero
Nino Ephraim
Explanation by phamtrong
Boot glass canon
Main Hero Supporting Hero
Ephraim Innes
Explanation by Alapizco
Magvel royalty do such a great team. With Ephraim's support, Innes can get +4 to all stats if they are next to each other (Thanks to Nidhogg). If surrounded by other two allies, that's +8 to all stats. If Ephraim has his common support build, that's +11 atk/+12spd/+12def/+10res to Innes. If Innes is your summoner support, that's 2 points more to all stats and +5 to hp. Disgusting.
Main Hero Supporting Hero
Ephraim Katarina
Explanation by SharpEyLogic
Basically any Blade tome user alongside Ephraim or Eirika. I feel that Katarina and Ephraim work the best since Katarina covers Ephraim's weakness to greens and Ephraim in turn defends Katarina against blues and physical reds. Nino and Eirika can be used to the same degree
Main Hero Supporting Hero
Delthea Bridal Cordelia
Explanation by JJLuigi
Both of these units are known to be incredible nukes, and pairing them up will not only allow them to be even more busted than they already are, but they can also survive more MUs with the speed boost.
Main Hero Supporting Hero
Brave Lyn Camus
Explanation by stranix
The new lyn is a beast,but she can use a partner. Thats where camus comes in. With lyn packing fortify cavalry and camus hone cavalry, they will turn into bow and shield. Not to mention the +2 to all stats. On top of that, lyn's good resistance and camus'es good defense means they can tank magical and physical attacks alike. Its recommended both of them run reposition, or camus runs swap
Main Hero Supporting Hero
Ike Delthea
Explanation by Zavenex
Given that Delthea buffs melee users anyways, bonding with Ike makes him all the more dangerous. If Delthea has her C slot skill as a spur/drive attack, that gives Ike a total of +10-12 attack. And all Ike has to do is stay still as he baits and decimates anything that dares attack him.

Futhermore, an Ike with both Fury 3 and Vantage 3 makes this bond even more frightening. Allowing Ike to further increase his OHKO potential.
Main Hero Supporting Hero
Summer Corrin (F) Hinoka
Explanation by Allerleirauh
S!Corrin benefits the most from this pairing, as she is the primary attacker in 9.9/10 situations. Hinoka* serves as a meat shield boosted by Corrin's Fortify Fliers while Hinoka turns Corrin into a nuke with her coveted Hone Fliers. S!Corrin and Hinoka are usually attached at the hip anyway, so the extra stat boost is hardly difficult to initiate. Reposition on Hinoka is also highly recommended.

*Hinoka can be subbed for any flier who has inherited Hone Fliers
Main Hero Supporting Hero
Hector Tana
Explanation by jamadama
With Guidance 3 equipped, Tana can airlift Hector across the field, while also fighting any red units that may threaten him. Positioned correctly, he can use distant counter to bait and protect Tana from bow wielders.
Main Hero Supporting Hero
Legion Brave Lucina
Explanation by AfricaByMowto
Brave Lucina is an absolute beast with handing out buffs. The +6 speed from the combination of her weapon and Drive Speed 2 can work absolutely wonderfully with units who can run brave sets well, such as Legion. Legion can very easily take care of Brave Lucina's enemies, such as bulky green and blue units and most mages with a combination of the previously mentioned Brave Axe+ and Desperation in combination with the HP loss from Fury 3 already on his base set. Lucina, on the other hand, can very easily handle most of Legion's enemies, which includes almost every red unit. This combination can be very deadly if played correctly and even deadlier if a dancer is tossed into the mix.
Main Hero Supporting Hero
Hector Eliwood
Explanation by i don't even know
These two childhood friends worked well together on the battlefield in Elibe, and the mini Tempest Trials are no different. With Eliwood's high res allowing him to tank more than a few non-blue magic hits and Distant Counter in Hector's arsenal, the two can take down mages left and right.
Main Hero Supporting Hero
Brave Roy Brave Lucina
Explanation by KaiokidGT
Probably the best duo in the game. Lucina's buffs gives Roy both the powers of God and anime. If Roy has reposition he can use it on Lucina after galeforce and get her out of harms way
Main Hero Supporting Hero
Brave Lucina Leon
Explanation by Asant
Adding on the extra edge with Brave Lucina's abilities, Leon can get an amazing 12+ speed boost with rally speed, even a neutral speed L&D Brave Bow Leon can pass 40 speed. Not to mention Lucina herself can tank herself(not mages) to keep Leon protected.
Main Hero Supporting Hero
Julia Nowi
Explanation by Mikestrike
Both already have well rounded stats and Nowi with fury and swordbreaker can wipe out any threat to Julia. While Julia's breath of life can support nowi and finish off anyone Nowi won't kill. (atk ploy seal is also an awesome help on Julia with her high res)
Main Hero Supporting Hero
Brave Ike Zephiel
Explanation by isopodshuffle
Axe Ike (Ake? Ixe?) pairs really well with DC Zephiel. Stick them with a DC Amelia and brave lance Effie power couple, then throw in some armor buffs and a couple of swaps/repositions and you’ve got an unstoppable wave of destruction
Main Hero Supporting Hero
Celica Linde
Explanation by daisyj201
Both are very powerful mages that can KO a wide swath of enemies. I gave both of them Renewal and Ardent Sacrifice, so they can act as healers in a sense. They can give an ally 10 HP and then regain that lost HP two turns or less later. Since they both have this combo, I often put them together anyway so they can trade off between attacking and healing, so it made sense to put them together as supports, too.
Main Hero Supporting Hero
Linde Olivia
Explanation by iFanz
Most Offensive team.
Linde with Fury on her will kill everything, with her Draconic Aura no one can stand her especially her speed after getting support. And Olivia will support her with her WOM, and Olivia also can give cheap damage to green unit so Linde can finish them off. I change her Hone Atk with Hone Spd so Linde cannot be stopped...
Main Hero Supporting Hero
Tiki (Adult) Ninian
Explanation by Sobrik
Double Dragon, 2017 edition. Factoring in Ninian's Fortify Dragons, this team-up makes a Fury A!Tiki almost unscratchable. If you have a +DEF boon on your Tiki, and invest your Summoner Bond in her as well, she's able to tank a number of blue units decently with a whopping total 51 DEF (with 53 ATK as well given that setup).

This makes her a solid check to / bait for Horse Lyn as well (assuming no Brave Bow) since she can still counter. Just... keep her away from Reinhardt and other blue tomes.
Main Hero Supporting Hero
Nino Ephraim
Explanation by Unlucky
The normal bladetome buff combo. Ephraim will deal with red units which is Nino's weakness while Nino destroy blue and even green units
Main Hero Supporting Hero
Mae Marth
Explanation by Elegear
Introducing the new support system, this dynamic duo can push Mae's speed to the heavens. (Marth can be replaced with Lyn)

Considering the player owns a +Speed / -Defense Mae with Fury 3, with the help of Marth/Lyn's Spur Speed, it is possible to bring her stats into an easy 35/51/45/17/35

And that's with one adjacent ally, Marth! With an Owl user as the main focus of a duo support, you can easily acquire a formidable ally that can never be doubled, as well as turning squishy glass cannon mages into a wall!

Owl tomes baby, it's time to hoot hoot in the horsehouse ayy lmao
Main Hero Supporting Hero
Nino Eirika
Explanation by Kyle1204
The pair has excellent synergy, with Eirika providing the buffs needed for Nino to dominate, and Nino dealing with the blue units that Eirika struggles with. Can be substituted for any buff bot + blade tome user pairing.
Main Hero Supporting Hero
Hana Delthea
Explanation by amroamro
Red sword glass cannon meets blue tome glass cannon. Delthea's weapon already boosts Hana's amazing power higher than ever. Now tack on 2 more ATK and SPD and she will decimate her foes. Delthea can take care of the tanky blue units that may trouble Hana as well as effectively duel other blue tome-users (even though Hana will have no problem dispatching them as well).
Main Hero Supporting Hero
Hector Lyn
Explanation by amroamro
Hector and Lyn combine forces once more to cover and bait each other's weaknesses. Lyn will be able to tank red and green mages as well as deal with sword units while Hector can lure the blue mages and deal with axes and lance users. Great for Mini-Tempest Trials (9/7/2017).
Main Hero Supporting Hero
Brave Lyn Brave Roy
Explanation by amroamro
Chosen heroes team up on their horses to form a vanguard with his rear support. Staying next to each other does them good since they love sharing a Hone Cavalry bonus.
Main Hero Supporting Hero
Brave Ike Brave Lucina
Explanation by amroamro
This unlikely duo form a team of chosen heroes that allows Ike to wield his Urvan with unprecedented agility. Just as his father Greil had Titania, all Ike needed was Lucina to master his father's memento.
Main Hero Supporting Hero
Eliwood Ninian
Explanation by amroamro
The fated couple return to form a decent hit and run tag-team. Very useful for the Mini-Tempest Trials (9/7/2017).