A character that is fully simulated is one whose actions are determined purely by simulation of the personality and inclinations of the character, given only the character's perception of his/her circumstances in the fictional universe. In other words, a participant who is fully simulating a character takes no OOC knowledge or objectives into consideration when determining the actions of the character. Consideration for the convenience of the plot is not considered.

The concept of full simulation of characters in storytelling is unique to roleplaying. In improvisational theater, a player is encouraged to always pay attention to the story so that everything his/her character does contributes to the performance. In Host A Murder type games, players will tend to cause characters to behave unrealistically or uncharacteristically in order to pursue the objective of discovering who the killer is.