FFXII: How to Kill Yiazmat

HP: 5,0112,254

Immune: All Status Effects
Elements: Weak to Dark. Absorbs Holy. Half damage for rest.
Technick Vulnerabilities: Expose, Shear

Abilities
White Breath- Area of Effect - Ice damage, chance of Stop
Stone Breath - AoE - chance of Petrify
Regular attack - physical + chance of Death
Rake - fast, 2x damage
Cyclone - Wind damage, chance of Sap
Deathstrike - Instant Death, single target, 100% unless target has Shell
Growing Threat - Doubles Level
Reflectga - Uses on Party

--Adapted from: Rodney Tilger's FFXII Mark Hunt Guide

Division of Labor:

Fighter: Vaan/Basch

Masamune

Hit hard and often

Healer: Ashe/Penelo

Orochi/Ninja weapon with Dark

Heal and recharge MP

Both: Fran/Balthier

Tournesol/strongest weapon*

Back up both

Tactics:

1. You'll need a full pack of Chronos Tears, Remedies, Gold Needles, Phoenix Downs.
   
2. Now's the time to use those Elixirs, Hi-Ethers and Megalixirs you were saving for a tough battle.
   
3. Be ready to switch gambits when you run out of one of the above.
   
4. Lower Yiazmat's defenses with Expose for a couple bars at start.
   
5. ALWAYS have someone attacking. Yiazmat doesn't do Deathstrike very often while he's being hit.
   
6. Keep characters bufffed with Shell, Haste, Bubble, Protect. Add Faith and Bravery when possible, keeping in mind #2.
   
7. Try to stagger buff spells so you're not having to do a bunch at once. When all 3 characters are attacking, that's a breather moment -- cast one buff.
   
8. Ignore the traps. They're just needles, 20-30 HP damange.
   
9. Once Yiazmat turns red and damage is capped at 6999, discontinue Bravery buff.
   
10. If everyone's keeping up, don't worry. But if you start running into trouble, move a fallen character(s) to the back in the Party Menu, turn OFF the Bravery and Faith gambits, bring in replacements, get things under control, have healer use Arise + L1 to target fallen member, bring fallen member back in to be re-buffed. That way backups are always buffed, and you never have two people effectively out of action (one KO, the other reviving the KO).
    
11. If you're in trouble, run back down the stairs and into the next room. Yiazmat will not regenerate HP while you're offscreen. Don't wait in the corridor -- he could COMPLETELY RENEW (I found out the hard way).

See below for my Yiazmat Battle Gambit Set-Up.

Etymology

According to the Final Fantasy Wikia, "Yiazmat" comes from FFXII directory Yasumi Matsuno's nickname, Yazmat, which is the name of the monster in the Japanese version of the game. The i was probably added to mimic the frequent Final Fantasy boss Tiamat.

That Wikia entry has some interesting rumors on why the director was "awarded" with this particular "Farewell to a Legend." My hunch is that the battle is a metaphor for what he put the development team through.