So reading through this thread, I tried the Runic tactic on Seymore. It didn't go as well as I was expecting, I should have stuck with my defensively geared strategy. He only cast single target spells twice through the whole battle, the rest of the time my team got decimated by AOE spells or physical attack. Ended up losing Cloud and Tidus, causing me to expert out. I feel like if I took sentinel's grimoire and protectga, I'd have been much further ahead. Valefor only did like 7k a turn, not worth the collateral damage for that. I'm not gonna bother trying again for now though, I did what I set out to do and unlocked the boss rush whenever it comes.
???
Seymour:
21% Multi Fira (BLK: 2 hits - 350% Fire Magic Dmg)
21% Multi Blizzara (BLK: 2 hits - 350% Ice Magic Dmg)
21% Multi Thundara (BLK: 2 hits - 350% Lightning Magic Dmg)
21% Multi Watera (BLK: 2 hits - 350% Water Magic Dmg)
16% Protect (WHT: Auto-hit Protect - Self only)
Seymour (weak)
25% Flare (BLK: 650% NonElem Magic Dmg)
15% Break (BLK: 33% chance of Petrify)
12% Multi Fira (BLK: 2 hits - 350% Fire Magic Dmg)
12% Multi Blizzara (BLK: 2 hits - 350% Ice Magic Dmg)
12% Multi Thundara (BLK: 2 hits - 350% Lightning Magic Dmg)
12% Multi Watera (BLK: 2 hits - 350% Water Magic Dmg)
12% Protect (WHT: Auto-hit Protect - Self only)
Mortibody
20% Desperado (PHY: AoE - 90% Phys Dmg)
17% Fire (BLK: AoE - 150% Fire Magic Dmg)
17% Blizzard (BLK: AoE - 150% Ice Magic Dmg)
17% Thunder (BLK: AoE - 150% Lightning Magic Dmg)
17% Water (BLK: AoE - 150% Water Magic Dmg)
12% Cura (WHT: Factor 55 Heal - Targets Seymour Natus)
Seymour has an 84% chance to
double cast a single target spell a turn, not doing any damage to the party and giving you two guaranteed summon charges via Runic, or protect on himself*, not doing any damage to the party. His attack pattern changes later in the fight but is just as useless against Runic
Mortibody has a 20% chance to use physical attacks, 68% chance to use an AOE that hits the entire party and gives you one summon charge via Runic, or a heal that does jack all.
"He only cast single target spells twice" is either hyperbole, or you were massively unlucky and he spammed protect on himself (which would be massively lucky on any strat other than Runic since his spells hurt).
Power and Magic Break on Mortibody is a given - not doing so vs incoming damage on any tough boss is asking for trouble. With the Runic strat, you don't even have to Magic Break Seymour, only Mortibody.
Valefor "only does" 7k. The silliness of that statement aside (you get infinite 7k casts without any buff/debuff requirement eating into your turn opportunity cost) it technically does more than that since it also hits Mortibody who then proceeds to absorb HP from Seymour.
I need to remember that when everyone here says an event/battle is easy, for me it's probably not. >_>
Probably true.
Everything is relative, and considering your abilities are r3, I don't think you should be expecting to have an easy time with what's technically endgame content just yet, cheese tactics or not. That trash is brutal even spamming instawin abilities like summons. The big bot is weak to fire though.