Brave Lyn

That should be Phantom spd 3, but with this build she will be able to take on almost any unit, besides some tanky mages, dragons, and healers but brave bow takes care of that while any physical attacker’s willl be unable to counter her because of her now 55 spd with buffs making it so no physical attacker will be able to counter her along with this Bonfire will deal with heavys with a lot of defense

Explosive Calvary Brave Lyn

Main strength: brave bow+ on slow enemies cause lyn to quad plus quickened pulse causing dragon fang only costing three=lyn gets an explosive head start if she manages to all four hits on the quad.( the rest is just smooth sailing)

Weakness: your gonna be pretty squishy, so watch out for attacks by other enemies

Brave bow+ =destroys mages and really just packs a punch ONLY IF YOU STRIKE FIRST

Life and death 3= Cancels out the brave bow spd decrease and adds adds 10-20 extra damage (usually)

Sacae's blessing- to get rid of distant counter so she can kill other units with ease

Ward Calvary(you can change it if you want, this one is optional)- provide some def for her allies since it's ALMOST useless for herself

Quickened pulse-if she pull off 4 hits in a turn the fourth hit will deal massive damage( happens only at the start of the fight)

Dragon Fang-that high damage headstart you can probably do if you quad

Reciprocal aid-more support since she's probably gonna die from almost anything( she can save lives or save herself)

*Best when used in Horse Emblem*

Life and Death 3 - Brave Lyn excels in her great attack and high speed, making her a perfect candidate to be a Brave Bow user. This skill gives her extra attack and speed to make up for the deficit lost through using Brave Bow+.

Sacae's Blessing - This is mainly aimed towards Arena runs. You can use Desperation 3 if you need to use her in Story maps or Chain Challenge. Distant Counter units are common to run into in the arena and Sacae's Blessing allows her to going into these match-ups safely. It is an immense help in finishing off units with Vantage since Brave Lyn will be able to attack without being hit first.

Fortify Cavalry - Can be swapped for other Cavalry skills depending on the team composition. Fortify Cavalry covers my needs in my team.

Brave Bow + - This is essential to bringing out her full power. She is fast and strong, so she wants to throw out as many attacks as she can.

Reposition: Can be swapped for other positioning skills. I find Reposition to be useful for ranged units.

Luna: Brave Byn wants to put out as much damage as possible, but most of the time she will run into units with decent to high defense. Luna allows her to pierce through them and if she is able to land four attacks, then she will be getting a Luna off guaranteed (unless enemy has Guard 3 or something similar).

Speed +1: It can be useful to have an Attack +1 seal on her as well, but generally being able to land 4 attacks makes up for trying to invest a lot into her attack.

Playstyle:

Brave Lyn is similar to that of Reinhardt, however she wins less match-ups than him. While she doesn't hit as hard as him, she makes up for it by being able to attack up to 4 times. Combined with Horse Emblem Buffs, she becomes a fearsome opponent. Brave Lyn is able to either ORKO units, or weaken them severely for another unit to finish, or for a dancer to come reset her to finish the job. Be mindful that she is not necessarily another Reinhardt. She has more counters than him which usually consist of armored units and Raven tome users (Ex: Triangle Adept Robin, Hector if she does not have Sacae's Blessing, and the random Henry you run into every now and then). This build has her at low defense and resistance, so she should try to go into safe match-ups and attack units that will keep her out of danger when she finishes her turn.

Brave Lyn is FEH's first Bow Cavalier and she's one of the best units in the game. With great stats for a cavalry unit and access to a great array of skills without SI, she's an example of what new units could be. Her primary advantage, however, is her ability to take horse buffs. With her already incredible statline she can make use of another weapon, Brave Bow+. Not only is she better than Bridal Cordelia at quad-ing, she also has a good enemy phase against mages due to her good Res and high Spd, even without the buffs.

This build centers around Brave Bow+ and her increased capabilities with horse buffs..
-For A skill we take her base skill Swift Sparrow. This skill takes nothing away from her defensive stats and boosts her player phase. Another skill that can be used is Life and Death which has 1 Atk/Spd higher than Swift Sparrow, however this makes trading against units that can counterattack much more harrowing and your enemy phase to be much weaker.
-For B skills we use her Unique base skill, Sacae's Blessing. This prevents physical melee units running DC, whether be it from the weapon or the skill, to counterattack. This helps her greatly as Brave Lyn's Def stat is abyssmal. Though she can still be counterattacked by dragons running Lightning Breath, she has a good enough Res to not take too much damage. Other skills that can be taken are Desperation for a more general B skill. Another skill is Cancel Affinity to counter Raventome/Triangle Affinity users.(IMHO this skill is too niche to be used compared to Sacae's Blessing, where DC units are in abundance.
-For C skills we use Horse Buffs to further supplement your cavalry team. In this case we use Fortify because it the buff that Lyn needs the least compared to a Bladetome user. You can also keep her base skill, Atk Smoke, a Clarisse Bow fitted into a passive. Another skill to take, if you have a Summer Gaius lying around, is the Gamepedia's venerable Def Ploy. Due to Lyn good Res stat, she can proc Def Ploy on most units she faces off against.
-For Assists we give her Reposition, a very good movement based assist to help other allied units get out of a sticky situation. Other skills are Draw Back if you don't have Reposition, or Ardent Sacrifice is you're running Desperation.
-For Specials we run Luna because your primary targets are usually slow but tanky. It helps to kills a unit that would survive all four hits. Because it's on a 3 turn cooldown, you can proc it on the 4th hit. Most target won't survive it. Other skills include Moonbow used with the Quickened Pulse Seal, and Draconic Aura.
-For Seals we have Atk+ for slightly extra damage, Spd+ to quad more units you weren't able to before, and Quickened Pulse is used to create a more fearsome first blood, utilized with Moonbow.

Brave Lyn is a great unit, with or without Brave Bow+. Do keep in mind your biggest threats are fellow bow users, Wary Fighter baits, Raventome users (when not running Cancel Affinity), and Brave Ike, who nullifies all Brave Weapon users AND cavalry buffs (and fliers too), both of which this build relies on. Suggest bringing a Brave Ike check when going to arenas.

Brave Lyn is such an obvious meta hard-counter, it's like IS said "fuck it". Now she's pretty much required for anyone who wants to continue using Horse Emblem because shes the only cavalry unit that has a chance against herself.