FFXII - Espers - Zodiark, Keeper of Precepts

Ashlesha Ascendant
Strongest of the scions created by the gods, they feared his growth, and so kept him a child. So indomitable is his strength that all things are by him twisted and pressed into oblivion. He alone fashions the laws governing all things, and administers punishment in place of the gods. So is he Keeper of Precepts, and his authority is absolute.

Previously seen in: Final Fantasy Tactics, as the final summon, used by Elidibs (the Lucavi hidden in the Deep Dungeon.)

Location: Henne Mines, Special Charter Dig. It's located in a secret area accessible from "Ore Separation" - the doorway (heading east) gets unlocked when you speak to the Geomancer in Jahara after having acquired 10 Espers.

Battle info
Status: Reflect, Protect, Shell, Haste
Weak: Holy, Absorb: Dark
Steal: Serpentarius
Attacks: Darkja (~6000 all + chance of Death & chance of Blind), Regular (~1600), Banish Ray (~8000 to one character), Greater Barrier (Protect + Shell), Mana Spring (?), Limit Break (?), Bravery, Magick Shield, Shift, Battle Cry (Blindga?), Paling, Faith, Reflect, Scathe
LP received: 70
LP to acquire: 200

Advice: Zodiark is the daddy of all Espers, which is ironic because it's really the youngest of all Espers. But man, is he a pain in the ass or what! First off, his major attack is Darkja, and while it's endurable it carries a strong chance of inflicting Death. Your party could have HP 9999 across the board, and all could die from a single casting of Darkja. For this reason, you'll want all six characters to have learned Arise. Banish Ray (the other big attack) is also dark-based damage, so you'll want equipment that absorbs dark (specifically, Black Masks) in addition to Bubble Belts. He likes to buff himself up with various spells, just Dispel whenever it happens, and Dispel fast: he'll eventually use Magick Shield, and if Faith is in effect while the Shield is up, well... his attacks will hurt all the more. Around HP Critical he'll throw on his Paling, and I hope for your sake he never has Paling & Magick Shield up at the same time.
In conclusion... Black Masks are handy to absorb dark, Bubble Belts are handy for topping 9999 HP, Arise is requisite for when you die (and barring a miracle, you WILL die), and deal with Paling and Magick Shield as they come.