Ultima Buster has two arms that shield the body against physical attacks, and its head will release its Contamination attack, which inflicts Poison (always), Zombie (always), Confuse, Full Break and Slow. The arms and head each have 80,000 HP of their own. The arms will regenerate after the body gets either three or four turns with both arms dead.
If the head is attacked between when it starts moving and when it uses Contamination, it will stop moving, and will not use Contamination.
The arms do not attack, but they shield the body from physical attacks. When shielding, the arms count as Ultima Buster having 255 defense and gains Armor status, regardless of whether there is one or two of them present. They do not protect the head.
It uses physical attacks and Ultima, that is a strong magic attack that hits all party members.
Another tactic for quick victory is to attack the arms and spare the head. All participating members should have maxed out Strength, Defense, and Magic Defense (in case Ultima Buster uses Ultima), then use Quick Hits to assure that Ultima Buster will retaliate in small chances.
[view·edit·purge]Ultima is Latin, and in many of today's Latin-based languages, for "The Last", in its feminine sense. However in the Spanish versions of many Final Fantasy games the spell name is "Artema", a closer transliteration of the original Japanese katakana.