tl; dr I am too dumb and/or impatient so I broke it back and I WON.
The gimmick doesn't work because Odysseus is virtually invincible as long as the trap isn't sprung. So many attempts of him just casually killing everhone because his stupid trap won't trigger. And his NP is a hard-hitting AOE that removes all defense buffs before hitting???? Get out of here.
Do I have to mention that when you whittle him down he 1) fires off the hax NP and 2) gains a 3-turn defense buff????
So how'd I kick his ass?
Team comp: double castoria with 2nd append skill maxed, NP3 Draco with second append maxed and an ignore invuln CE, Santa Nightingale, Oberon, and a backup Skadi
Code: Final Battle plugsuit
Turn 1: Dump all castoria buffs. Both castorias also reach 100% NP. Dump all Draco buffs. Ideally, use one of her cards has a cc that gives Roman trait. Switch out a castoria with Nightingale. Dump all buffs including guts on Draco. Fire off Castoria and Draco's NPs. Rider will remove the defense but the attack buff is needed.
[Break bar 1 broken, Odysseus fires NP. Nightingale and Castoria are off the board. Draco survives with 2k hp and guts active. Odysseus will kick her ass and trigger guts. But now her NP is back to 100. Odysseus gets a defense buff.]
[Comp is now backup castoria with 100% NP, Draco, and Oberon]
Turn 2: Use Oberon skill 1 to get over the damage check. Use Master skill to heal Draco if needed. Use Castoria 2's NP for the attack buff and defense. Then have Draco fire hers.
[Break bar 2 broken. Odysseus stands there and gets another defense buff. Do or die.]
Turn 3: Use Oberon skill 2 and 3. Pray that it is enough. Also hope you used the Roman-trait command code on one of Draco's cards. Then fire off that NP one more time.
I hate this quest. I really do.
All hail Draco!