A person-like being who exists and acts in the game world much as the player would.
IF borrows terminology from fantasy role-playing games such as Dungeons and Dragons, in which the characters whose actions are controlled by human players are known as player characters (or PCs), and characters controlled by the dungeon master are known as non-players characters (or NPCs). Thus Nick Montfort (2003) describes a character in interactive fiction as "a person in the IF world who is simulated within the IF world," including both PCs and NPCs as they are understood in IF but not including those people who are simply mentioned in the text, but are not present in the game world as objects with which the player may interact.
Character can also be used in the ordinary literary sense, referring either to the personal attributes of a PC or NPC, or to a figure whose "off-stage" actions advance the narrative, or who played an important role in the backstory (e.g. the artist in Galatea (Emily Short; 2000; Z-code).