Absorb (ability)

Eater is a recurring ability throughout the entire series, and refers to often to the ability of absorbing elemental attacks and converting the damage to HP recovery. Although the ability was not given a name until Final Fantasy X, it has been a predominant ability and a rather crucial ability throughout the series, especially against enemies and bosses of particular elements that can only use attacks of that element, and by using an Eater ability against said enemies and bosses, renders them completely harmless.

Final Fantasy X
The first time that the abilities were given any names, and thus named Fire Eater, Ice Eater, Lightning Eater, and Water Eater. They can be found on various dropped armor, or customized onto armor by using 20 Fire Gems, Ice Gems, Lightning Gems, and Water Gems respectively.

Final Fantasy X-2
Fire, Ice, Lightning, and Water Eater all return as well as the addition of Gravity Eater, Holy Eater, Tetra Eaterand Omni Eater.