How to beat legion ghb infernal.

Yeah, I'm also having trouble. Good thing these things cost 0 Stamina, am I right? ;)

Edit: Just took a crack at it a few times and I finally beat the lovable bastard.

My Trusty Steed - +Def -HP Donnel - Berkut's Lance, Aether, DC, Vantage, Threaten Def, QR

My Forceful Tactic - +Spd -Res Siegbert - Dark Greatsword, Dragon Fang, Death Blow 3, Desperation 3, Atk Tactic 3, Brash Assault 2

My Flying Singer - +??? -??? NY!Azura - Sing, Earth Dance 3, Guidance 3

Abs - +Spd Sothe - Peshkatz, Glimmer, L&D3, Desperation, Spur Atk/Spd 2, Heavy Blade 3

So yeah, it was a bit tricky, especially since Legion's axe inflicts Panic, but... yeah. :)

Phoenixmaster1 usually has some helpful videos for dealing with GHB's and the like so feel free to check him out to get some ideas. Even if you can't replicate the exact teams that he uses, it sometimes helps you get part of the way.

General advice, I'd say you need a strong red unit to consistently deal with all of the Legions, preferably that can OHKO so that they don't sustain too much damage. Brave sword or a strong Desperation user is probably best. (Elincia fit this role for my team.)

Aside from that you really need a strong offensive core instead of something tanky because if you don't quickly deal with reinforcements they can get really overwhelming. I also had Draw Back or Reposition on each of my units to make sure that they could deal with certain reinforcements but get moved back to safety.

And for the record, when this GHB was first released I couldn't even make it past Lunatic - it's tough, but don't get discouraged. Good luck!!

I ended up using horse emblem, mage focused. Not sure if you'd have units that could fill a similar team but it worked fairly effectively for me.

Team was Gunnthra, SM!Eirika, Bowbreaker Reinhardt, and Eldigan.
Eirika and Gunnthra did most of the carrying, Eirika taking out most of the Legions and other red reinforcements and Gunnthra handling the blue units. Reinhardt mainly just killed the Brave Bow and baited the red mage turn one. Reposition was also very important as it allowed Eirika to kill things then be safely brought out of enemy range. Especially turn 1 where Eirika could kill the Legion on the right and Gunnthra reposition her out of the range of the blue mage cav that Gunnthra could handle easily on enemy phase.

It helps if you provide a sample list of units that you have and/or those that are decently built. Generally, a Red unit with solid bulk can deal with Legion, and a DC user like Fjorm should help a lot with the Ranged units.

If you are interested in what I used, I ran an Armor Emblem team consisting of Amelia (+Def/-Res), Black Knight, W!Tharja (+Atk/-HP), and VA!Lyn (+Atk/-Spd). (I know this isn't the most practical solution, but in case anyone has these units, I thought that it was worthwhile to put down anyway.)

It’s super cheesy, but Brave Lyn w/Desperation plus 3 dancers w/ WoM....never fails me

A strong red mage (I used Triangle Adept Lyon) with axebreaker and an archer who can easily down the mages (I used Brave Bow Val.Roy) will serve you well. I used Frederick to oneshot random blues and some legions (axebreaker, again), and legendary ephraim was just kinda there to reposition and weaken some enemies.

It took me a few tries but my trusty Flier team of S!Corrin, Legendary Robin, S!Kagero and Elincia beat infernal. Surprisingly I'm having more trouble with the blessing quest.

It's been a while but I remember doing it with a Brave Bow+ Klein with Axebreaker 1, 2 dancers, and an Olwen, who was my only fast, high-res blue mage at the time.

I used Xander (Bonfire, Steady Stance 3, QR2, Hone Cavalry), Olwen and LA!Lilina (both bladetomes). Olwen baited the two first mages using the bottom left defensive tile then Xander takes the Legions with the mages sniping to help out. Kill everything that spawns at the bottom quickly then Xander sat on the defensive tiles taking damage from the mounted lance only and Bonfire letting him deal big damage to the it and the Legions, helped out by their Fury recoil. Had to watch out for Panic Ploy on the bladetomes so brought Reinhardt as well but all he did was kill a mounted sword that spawned at the bottom.