Trails in the Sky 3rd: Chapter 6 Cassius Battle Nightmare

Описание: You're up against The Man Himself, and it shows.
He's so strong that he doesn't even need any backup to be a serious threat to your party.
This battle is quite hard but very straightforward since there is only one foe.

Prep:
Earth Wall or Gaia Shield usable on at least 2 characters
(La) Tear-All on multiple characters
All characters should have 18k+ HP so they can survive a Lightning Flash or Armor Rend
Put the Physical Quartz on Richard (lowers damage taken)

Strategy:
Buff up (STR - DEF - SPD) on all characters
Keep Earth Wall on everyone (it's smart to use "Move" on your other EW caster if he has a free turn with nothing else to do)

The real fight begins when he uses his buff, at which point he becomes much faster.
Save Kevin's S-Craft until he uses that, and use it to cover for when you can't cast Earth Wall in time.

If the fight goes south and he's on low HP, you might be able to salvage it by spamming Richard's Crafts and using Tear-All to stay alive and using his S-Craft at the end.

Cassius seems to be immune to all status effects and debuffs, so don't bother wasting time on those.
There are some elements of luck involved depending on whether he uses his single target attacks or the area ones (esp. Armor Rend is devastating), but other than that this fight is fair.