An A.I. Companion is a computer controlled non player character (NPC) which closely follows the protagonist during any given portion of a video game. Sometimes they may strictly follow directly behind the player characters exact footsteps, other times they might loosely follow along an invisible series of guideposts created by the player characters movement, constantly trying to follow within a set distance but free enough to assist the player in a more complex way during a game event.
Examples and Variations
There are several different popular methods in which a game may attach a Tag Along NPC to the player character. Many top down RPGs "railroad" members of the protagonists party behind him/her while the main character is walking from place to place, typically having 2 or 3 party members follow along in a chain. Within the PS2 game ICO, "holding hands" is used to attach the player controlled protagonist (Ico) and a tag along NPC (Yorda) together for much of the game even while the protagonist is fighting. In some games, the NPC is an animal companion rather than a human, such as the dog Hewie in Haunting Ground or the horse Agro in Shadow of the Colossus.