Aggro is a term used in MMORPGs and other online games to refer to monsters which attack player characters without any type of provocation. Monsters which do not attack this way are usually called "Docile". Docile creatures will only attack the player after an offensive action has been performed against them.
Aggro can refer to the action of a monster attacking a player or it can refer to the monster itself.
Synonyms for aggro include "Aggressive" and "Enmity", although the latter is also used in many other cases and the terms are not always interchangeable.
In Final Fantasy XI the term is often used by players, especially when attempting to sneak by powerful mobs undetected, or during partying in which unwanted aggro could be dangerous to the party's success as a whole. Deliberately causing monster aggro is a form of pulling.
Monsters means of detecting players to attack are often described in terms of aggro, as follows:
- Sight aggro means that a monster aggros when a player is its line of sight. Monsters with True sight are not fooled by Invisible.
- Sound aggro means that a monster aggros when a player is in a small radius nearby. Monsters with True sound are not fooled by Sneak.
- Magic aggro means that the monster aggros a player who casts spells nearby.
- Blood aggro means that the monster aggros a player whose HP is in the yellow or lower.
- Job ability aggro means that the monster aggros a player who uses job abilities or Weapon Skills nearby.
Most aggro monsters will not aggro players if they /check as "Too Weak to be Worthwhile" to that player; however, /healing or /sitting players can be aggroed by monsters of any level. Any monster that is naturally asleep as indicated by animated "z"s rising from it will not aggro by any means, although it will wake up if attacked.
It is worth noting that the means by which monsters track down fleeing players is not necessarily the same as the means by which they aggro players in the first place; in particular, mobs that aggro by hearing usually track by scent, which can be foiled by the spell Deodorize, the item "Deodorizer", or the simple expedient of running through a shallow body of water. For normal monsters, players who manage to put a sufficient distance between the monster and themselves will lose aggro. When this happens, the monster will go after the character with the next highest enmity; if there is no such character, the monster will turn and walk back to its spawn area. If the monster is far enough away from its spawn area, it will despawn entirely.
Many monsters have a quality known as linking, where they will aggro any player who is attacking another mob of the type that they link to. Linking mobs typically link to their own type and sometimes another related type, such as saplings linking to treants.
When a monster aggros a player, normally it only aggros that player and not the player's pets, party members, etc. However, a few monsters have Party Hate, meaning that if their initial aggro target dies or escapes somehow, they will then turn to track down if necessary and then attack another party member even if that party member did nothing.
In Final Fantasy XII, unlike many other Final Fantasy titles, the battle system occurs in real time, rather than the traditional turn based system. In addition, monsters are seen on the overworld map prior to engaging them in battle. Because of this, "aggro" can refer to aggressive monsters in this game as well, despite the fact that "aggro" is usually only seen in MMORPGs.