Enmity

From Final Fantasy Wiki

Enmity appears in Final Fantasy XI as a term that refers to the hatred an enemy feels for any particular player. In theory, every player in the same area as a creature has an enmity score. A creature will attack the player who he has the greatest enmity against. If the creature hates no one, he will generally just stand still, walk a path, or roam depending on how his behavior is set.

Enmity also appears on items. When an item mentions that it has "Enmity +2" that means that every attack, spell, or ability used against the creature or in aid of another player who the creature has hatred against will produce more enmity than normal. Gear that increases enmity is sought after by tanks, particularly Ninjas, who lack both abilities to create much enmity on their own or the ability to do great damage.

If an item lists "Enmity -2" then that means an item will make that player's actions generate less hate in a battle situation. These type of items are generally sought after by casters, in particular, White Mages.

A player will lose all enmity in an area when they move from one zone to the next. Enmity can be cleared also under special circumstances. The most common of these are Dragoon's Super Jump ability or enemy abilities that cause area of effect stun. All stunned creatures will lose most of their enmity ranking, but mages, who are probably standing far enough away to avoid the effect, will keep theirs which means the enemy will come after the mages. Character death will also erase enmity.