Bound Hero Battle: Cecilia & Lilina

For Hard, Lunatic, and Infernal.
Eldigan and Cecilia are replaceable. The one unit really needed is Camus with Vantage, and to a lesser extent Reinhardt with Lancebreaker. Cecilia and Eldigan supply Fortify and Hone Cavalry respectively. Eldigan can be replaced with any (horse unit ideally) that can take out a weakened Cecilia, so just about anyone. Cecilia can be anyone.

*On Hard, Camus baits Cecilia, Lance Cavalier, and Lilina by moving into nearest red space. He can kill all of them on response. On the next turn, he can also handle the Lance Flier, and Reinhardt handles the Bow Cavalier.

*On Lunatic and Infernal, instead break the wall in front. Use Reinhardt to quickly take out the Lance Flier and have Camus use Reposition to get him back to safety, leaving Camus in the danger zone. Camus can take the subsequent attacks from Cecilia and Lilina, killing Lilina with Vantage and Bonfire. Next turn, Eldigan can finish off Cecilia and Reinhardt can take out the Lance Cavalier. Next turn, Reinhardt takes out the Red Infantry Mage (Infernal only), Eldigan chips at the Bow Cavalier and Cecilia uses Reposition to get Camus in range to finish it off.

Necessary/helpful skills:
5* Camus:
Reposition
Bonfire
Fury 3
Vantage 2
Goad Cavalry

5* Reinhardt:
Luna
Death Blow 3
Lancebreaker 1
Ward Cavalry

5* Eldigan:
Hone Cavalry

4* Cecilia:
Reposition
Fortify Cavalry

I have a -ATK Reinhardt and a 4* unbuilt Cecilia, this strategy's pretty flexible.

Build:
Cordelia:
Weapon: Brave Lance+
A- L&D
B- Pass (Not needed)
C- N/A
Support: Reposition (Needed)
Special: Galeforce
Seal: Attack (Not needed)

Merric:
Weapon: Excalibur
A- Attack
B- Lancebreaker
C- Spur Res (Not needed)
Support: Drag Back (Needed)
Special: Ignis
Seal: Quickened Pulse (Needed if running Ignis)

Olivia:
Vanilla

Instructions:
Cordelia's job is to kill everything besides the Cavalier and Flier.

Part 1:
Starting off, we want to simply destroy the first block. From there, DO NOT buff Merric, if you do he can potentially OHKO the flier. After the block is destroyed, position Merric right in front of the broken tile, with Cordelia directly behind him. Make sure that Olivia is in range of Merric, not directly beside him.

Part 2: Attack the Flier with Merric, and it should take two shots to kill. If you have Ignis, your special should be at 1 now. Use Cordelia to Reposition Merric. From there, dance on Merric and use Drag Back on Cordelia to remove her from enemy range.

Part 3:
Everyone will pretty much mob rush you here, which is what we want. Cordelia should be in range to attack both Lilina and Cecilia from below the broken tile. Cordelia is capable of killing both, so it doesn't matter the order. Use her to kill Lilina, then with Olivia Dance, and kill Cecilia.

Final Part:
Galeforce activates. The archer should be right beside a newly broken tile (2nd one). Kill him. Merric comes in, and with a hit and Ignis proc, the lancer goes down. Next turn kill the red mage that followed behind the lancer.

IMPORTANT NOTES:
Merric is not mandatory, but you should have a high damaging green mage that can successfully take care of both blue units. Drag Back is mandatory.

Cordelia is not Mandatory. As long as you have a high damage/speed Brave user that is NOT using a sword and has Galeforce, they can work. Reposition is mandatory.

Dancer is mandatory.