FSIII - Arena Hidden Battle

To beat this boss, you should have Subclassed Ethan with his relics at level 99 and Ethan at level 99.

Go into the Arena and do matches until you have 10000 popularity. Then, do the Solo C-rank Arena as Ethan. Make sure he has max SR and don't use any SR skills during the Arena matches.
I also recommend you give him either the Haste Ring, or put SP into Agi.

I recommend you have the Regen Arena Armor to make Ethan's life slightly easier. Make sure to summon often and keep your summons alive; they make the later part of the arena much easier.

Then, you will receive a challenge from team Faith. Zeika will challenge you.

BOSS: Zeika
HP: 65000
MP: Irrelevant. Too much to waste, and he can't be drained.
Timer: 10 minutes

750 P/M DEF
950 AGI

~ Magic Charge
~ Triple Multi Slash
~ Falling Bolt
~ Cure 3 (~50% HP)
~ Holy Pillar (~50% HP)
200% Fire
200% Ice
-100% Earth
0% Wind
150% Darkness
-200% Nature

Cannot be Frozen
Cannot be Poisoned
20% Chance to be Silenced
Cannot be Confused
20% Chance to fall Asleep
Cannot be Time Stopped
Cannot be Zombified
Cannot be Doomed
Cannot be Burnt
40% Chance to be Soul Cursed


This battle is one of the hardest in the game. Seriously.
On Turn 1, Summon your Healing and Support relics.
For Support Relic Turn 1: Cast Relic Barrier on Ethan
For Healing Relic Turn 1: Heal anyone if wounded, or cast Healing Aura on self.

Ethan Turn 2: Cast Soul Reflection EX.
Support Relic Turn 2: Nothing
Healing Relic Turn 2: Nothing

Next turns: Ethan spams Icicle Spear Barrage on Zeika, and Healing Relic keeps Ethan healthy. (Remember not to cast supportive skills while Reflect is up!)

There you go. That's how you win.

An alternate strategy is to use Subclassed Aria and her Slow, since he has a 60% chance of being slowed. However, this strategy is not as reliable as the above.