Grand Lethal is a Dyne ability in Final Fantasy IX used by Zidane while in Trance. It deals physical damage to one enemy for a cost of 60 MP. It is Zidane's ultimate ability and also the most expensive.
Obtained[]
Grand Lethal is available when Zidane has access to Thievery. Thievery is learned for 100 AP from Angel Bless and late on from The Tower. Angel Bless is synthesized in Alexandria, Treno, Lindblum (after returning from the Outer Continent), Daguerreo, and Black Mage Village (the endgame) for 9,000 gil, a Mythril Dagger, and a Gladius.
Mechanics[]
Grand Lethal deals quadruple the damage of Zidane's normal attack to all enemies; his power is already enhanced by being in Trance. Despite the animation, the damage is physical and non-elemental.
Damage is calculated as follows:
- Base = [(Attack * 40) / 10] - Enemy Defense
- Bonus = Strength + Rnd MOD ([(Level + Str) / 8] + 1)
- Damage = Base * [Bonus * 1.5]
Bonus is halved by target's Protect, and is reduced to 1 while Zidane has Mini.
Use[]
Grand Lethal is Zidane's ultimate ability, dealing easy 9999 damage to all enemies. It is expensive to use at 60 MP, and because of the damage cap, Zidane may be better off using Meo Twister (250% damage to all enemies) or Shift Break (200% damage to all enemies) against groups for similar damage but for much lower MP cost. There are no boss groups, so the only times group-hitting Dyne skills are preferable over single-target ones is in random encounters, and the only tough group is against Yans where Zidane already has an excellent non-Trance strategy with Masamune + Soul Blade. Against bosses, Grand Lethal is still stronger than the preceding Solution 9, which does triple damage in comparison to Grand Lethal's quadruple damage, however, due to the damage cap, they may both effectively do 9999, the difference being that Solution 9 cheaper to use. Grand Lethal can be great against the final boss who uses Protect itself to hopefully hit the damage cap regardless.
When Zidane uses Grand Lethal, several beams of energy lance out from Zidane's body, striking all enemies. With each hit a symbol in Terran script 
appears in the explosion of the impact.
The downside of all Trance abilities is that timing them for a battle where Trance would be most beneficial, like a boss battle, is difficult/impossible, as a Trance state cannot be saved up, and its building does not depend on the amount of damage sustained from enemy attacks, only the number of enemy attacks taken. The only ways to expedite Trance are to use High Tide and Protect Girls for Zidane to intercept attacks directed toward some of his allies. As Zidane may enter Trance in practically any battle, it is the luck of the draw whether his improved physical prowess is a bonus for that particular encounter or not.