From Final Fantasy Wiki

Final Fantasy IX Enemy
Beatrix
Statistics Level HP MP 1. 14 2. 17 3. 17 1. 3,630 2. 4,736 3. 5,709 1. 3,467 2. 3,964 3. 4203 Strength Magic Power 1. 22 2. 27 3. 29 1. 11 2. 12 3. 12 Defense M. Defense 1. 10 2. 10 3. 10 1. 12 2. 10 3. 14 Evade Magic Evade 1. 3 2. 3 3. 3 1. 4 2. 4 3. 4 Speed Spirit 1. 41 2. 42 3. 47 {{{Spirit}}} EXP AP Gil N/A N/A N/A
Elemental affinities Fire Ice Thunder Water - - - - Wind Earth Holy Shadow - - - -
Japanese	ベアトリクス
Romaji	Beatorikusu
Location	1. Burmecia 2. Cleyra 3. Alexandria Castle
Class	Humanoid
Steal	1. Phoenix Down, Chain Plate, Mythril Sword 2. Phoenix Down, Thunder Gloves, Ice Brand 3. Phoenix Down, Ice Brand, Survival Vest
Item Dropped	N/A
Card Dropped	N/A
Abilities	1. Thunder Slash, Stock Break, Shock 2. Cure, Thunder Slash, Stock Break, Shock 3. Cura, Thunder Slash, Climhazzard, Shock
Eat	N/A
Status Immunity	Petrify, Venom, Silence, Darkness, Trouble, Zombie, Death, Confuse, Berserk, Stop, Poison, Sleep, Regen, Float, Heat, Freeze, Vanish, Doom, Mini
Other Information	None of the three battles can be won.

Beatrix appears three times as a boss in Final Fantasy IX. Beatrix is massively powerful with her many strong attacks, and can heal herself with White Magic. If this was not enough, the game is fixed so that Beatrix does not fall in battle even when her HP is supposedly depleted. She is also immune to all status effects except Slow. The best the party can do is stay alive until she uses an unblockable finishing move that instantly knocks them all down to 1 HP; either Stock Break or Climhazzard. She also uses the Shock attack to do massive damage to a single party member. If the party is defeated before this, it will be a Game Over.

She can be stolen from, however, and furthermore she has many good items to steal, so your mission should be to keep Zidane alive so that he can steal all the items in the three battles. Once they are stolen, just keep the party alive until Beatrix uses Stock Break or Climhazzard.