Trails in the Sky the 3rd: Cassius (Nightmare)

Honestly not too terrible of a fight, but good RNG is required and you really need 20k+ HP just to survive a basic. Just make sure to burn him down before he can burn you down, Set-up is shown at the end. Renne honestly isn't necessary but she is really good so probably use her if you struggle, Olivier should also fit the role nicely, but he's not as good. Schera also isn't required but the AT Advance can save you in a pinch and she's a decent caster.
Main Idea here is to just have Richard burn him down and everyone else on support. Cheers.
Comment any questions if you have them and I'll try to help :)