Bot

A bot is an computer-controlled player with an AI that accesses the game's internal data so as to know where it is and where its targets are found. Bots can be designed to attack monsters (for single-player or cooperative games), to attack fellow players (for deathmatch), or both.

Though a bot is normally a player, some mods feature "coop bots" that are in fact friendly monsters scripted to have attacks similar to those of the player.