Bound Hero Battle: Cecilia & Lilina

https://youtu.be/aPk48wGGpYg

Olivia is literally level 1 so any dancer will do
Delthea's +HP - Res and has Quickened Pulse Miracle(hence the title) and Reposition
Legion Has Fury and Infantry pulse
and Clarisse is a standard brave bow set up so any brave archer should do

B.Cordelia - Life Death Brave bow build w/Draw back
(+ HP bias - def)
Hector- Distant/Wings of Mercy/Threaten Build w/ Draw back
Ninian- Wings of mercy Build
Reinhardt- Glass Cannon build w/ reposition

Phase 1: the setup
Place You units up to danger zone with the front debris cleared. place your units in the following order:
B.Cord/Ninian
Rein/Hector

Phase 2
Combat
use Cordelia to destroy the wing lance. use rein to reposition, dance cordelia to draw rein away from danger zone, hector draw back ninian (this is a must for hone attk.)

Phase 3
Combat
Cordelia destroys Cecilia with 1 Hp remaining. use reinhart to destroy Lilina on the top square in front of B.Cordelia. this ensures rein does not die to lance
Escape route hector moves under Cordelia to taunt Lance unit to attack him. Move ninian away from danger zone via spawn area (doesn't matter, her WoM will come in play next turn, keep her safe)

Phase 3
Combat evasion mode
Blue lance suicides into hector, brave bow moves up. red mage moves up. move rein to the top right corner to avoid getting bow'd. move cord up below rein. hector wings of mercy in front of cord. keep ninian safe.

Phase 4
Victory
Red mage and bow will move up. Rein deletes Bow,Wings of mercy Ninian teleport up to Rein, dance, rein destroy red mage.

Units I used:
Ike: +atk/-hp, fury 3, vantage 3, hone atk 3, reposition, glimmer
(only actually need vantage 1, draconic aura can be used instead of glimmer)
Reinhardt: +def/-spd, death blow 3, lancebreaker 3, hone spd, draw back, bonfire
(+atk is better of course, luna is also better than bonfire, especially if yours isn't +def)
Virion: Virion's skills dont matter, all he did was break a wall. He can be replaced with any ranged unit. I personally used a 1 star level 1 Virion.
Summer Tiki: fortify res 3
summer tiki can also be swapped out for any unit with fortify res 3, because she does not participate in combat either. In fact, by putting the HP +3 sacred seal onto my Ike, I was able to do it using a 1 star level 1 gunter instead.

Strategy:
Reinhardt should start in the top left spot, Ike should be in top right, virion in the bottom left, summer tiki in the bottom right.
To start off, move them all up one space.
Next, have Virion break the wall above Reinhardt.
Have Reinhardt attack the lance flier. Lancebreaker means he will hit 4 times total, activating his special and killing despite the 40 res.
Use Ike to reposition Reinhardt behind him.
End your turn.
On the enemy's turn, Lilina will attack Ike and leave him at 2 health, reduced to 1 after combat due to fury, but Ike will retaliate with 2 hits, killing her and charging his special. Cecilia will then attack him but will die to Ike's special before being able to hit him thanks to vantage.
Next, kill the Lance Cavalier with Reinhardt.
Move Virion so that the red mage can not kill him.
End your turn.
The enemies will not be able to attack anyone on their turn.
Now, attack the red mage with Reinhardt from over the wall so that he is not in range of the archer.
Move Ike down as well so he is not in range of the archer either.
End your turn.
Finally, kill the archer with Reinhardt.

Some notes:
I think a +atk Reinhardt with Luna would make Ike's Hone Atk 3 wholly unnecessary, as he would still be able to kill the enemies he needs to.

I also think using a +atk fury vantage ryoma instead of Ike would make the Fortify Res 3 unit unnecessary because he has 3 more res naturally, and would survive lilina with 1 health unaided.

Okay this team's called the handsome Ike since he is the one to kill both Celicia and Lilina. So cool (๑>◡<๑)
*Ike
My choice is Ike but you can choose any other sword users as long as they have distant counter, strength high enough to kill Celicia in one hit (of course with hone attack) and hp high enough to take one hit from Lilina
Special skill: glimmer recommended cause the cooldown is 3 and is enough to kill Celicia
Passive: reposition
A: +4hp
B: vantage (any will do cause after one hit from Lilina he'll have 1 or 2 hp left
C: N/A
Seal: +3hp
*Nino
Boon speed is preferred
A: fury 2
B: desperation 3
C: hone attack
Special skill: moonbow
*Robin (M)
A: triangle adept 3
B: anything
C: hone speed 3
Passive: reposition
Special skill: anything
*Olivia or any dancer with hone attack
Turn 1: move nino to the upper right and destroy the nearest wall, followed by robin, ike in single file, olivia next to ike
Turn 2: move nino right in front of the broken wall, dance then kill the lance flier, reposition ike, use ike to reposition nino back behind him.
Turn 3: kill the cavalier with nino, dance her and reposition her with ike, use her to kill the bow user. Finally, kill the red mage with robin.
That's it for infernal mode. Thanks (*⁰▿⁰*)

For this team (Y) Tiki needs at least 33 speed and needs fortify dragons. Use these buffs to bait both mages after you use Nino to kill the blue unit next to Lilina. Then you will need reposition on Tiki to bring both units you use up top (Nino and Azura). Then both mages will attack and so long as you have a neutral res on Tiki with the fortify dragons she will survive. Now you want bonfire or a 3 turn special that boosts her atack then you will kill both mages with her and if done properly Tiki will be safe from the bow man. Then use nino to kill the blue units comming from the left. You wioo then need to bait the bow man with ninian who needs to be at atleast 28 def and have at least 43 hp. Then use Tiki and a dance to kill the bow man. Once this is done you clear up the red mage with Azura and use Nino for all and only the blue units. Wings of mercy 1 or avove helps with Azura's movment but isnt required.