AI Player Personalities

AI players can be weaker or stronger, but it's not always fun, and not even always clearly defined. Thus, there are AIs that differ from their peers with optimization criteria and biases in decisions, which makes them stronger or weaker than others depending on the situation. Among the other things, AI behaving differently makes each game different, improving replayability, and different behavior makes them more human-like.

Video Games

 * Armada 2525 has personalities randomized, but you can use "Set Personalities" option. Personalities have 3 components: tactics (how they act in a war - Cautious / Prudent / Reckless / Manic), strategy (overall development - Industrialist / Technologist / Ecologist / Militarist / Expansionist) and stance (diplomatic inclinations - Peaceful / Isolationist / Defensive / Aggressive / Xenophobic).
 * Master of Orion (and Master of Orion 2) has personality (Ruthless / Erratic / Aggressive / Pacifistic / Honorable / Xenophobic) and objective (Diplomat / Militarist / Technologist / Ecologist / Industrialist / Expansionist).
 * Master of Magic has a similar system - Personality and Objective. Personality influences diplomacy and spellcasting, tweaks decision-making with special procedures and is on the scale of viciousness: Maniacal, Ruthless, Aggressive, Chaotic , Lawful , Peaceful - "core" diplomatic reaction to other wizards increases, while hostility (also affected by difficulty setting) and likelihood to declare a war or perform a hostile action (by army or overland spell) decreases; also, Lawful and Peaceful don't perform a hostility evaluation at all no matter Objective and difficulty setting, thus always remain friendly and unless forced to declare war won't "move toward" it. Objective influences preference in building and other resource spending: Pragmatist , Militarist , Theurgist , Perfectionist , Expansionist ; Militarist and Expansionist without Peaceful or Lawful personality are more likely to break treaty and start a war.
 * Moreover, the probabilities of traits depend on the wizard's primary realm (the one which has the most books and defines Familiar sprite for the human player; an unofficial patch also considers secondary realm to lesser degree), so there are observable trends. Nature: Lawful Perfectionist, Sorcery - Aggressive Theurgist, Chaos - Chaotic Militarist, Life: Peaceful Perfectionist, Death: Maniacal|Ruthless Expansionist|Militarist. "Retorts" (non-book options) also prefer some Personalities and/or Objectives: Nature Mastery: Lawful Perfectionist, Sorcery Mastery: Aggressive Militarist , Chaos Mastery: Chaotic Theurgist, Divine Power: Peaceful Theurgist , Infernal Power: Maniacal , Alchemy: Perfectionist , Archmage: Theurgist, Chaneller: Ruthless Expansionist, Conjurer: Aggressive Perfectionist , Mana Focusing: Theurgist, Myrran: Chaotic Expansionist , Sage Master: Lawful Theurgist , Warlord: Aggressive>Ruthless Expansionist>Militarist.
 * Wing Commander pilots have most of the stats to define behaviour: Aggressiveness (more eager to engage, but less resistant to distraction by taunts when already attacking someone), Carefulness (expending energy and ammo, ranging from wasteful to conservative), Courage (whether the pilot will hightail after the first hits or always fight to death), Flying skill, Gunnery skill, Loyalty (willingness to obey in-flight orders, ranging from never to always) and Verbosity (probability of random chat/taunt, and for Human pilots, but not enemies also inclination to fly unpredictably and with more fancy manoeuvres than necessary).
 * In Perfect Dark's multiplayer mode offers "normal" personalities on the scale of Artificial Stupidity and The Computer Is a Cheating Bastard as well as a bunch of special personalities. These include one that only uses melee attacks, one that always attacks the last player to defeat it and one that only attacks "weak" opponents among others.
 * Pawns in Dragon's Dogma have several mutually exclusive parameters that will influence their personality based on their master's behavior. Unfortunately half the possible personalities are useless. For example "Guardian" pawns stick close to the player to protect them which sounds good, but in practice it means they ignore enemies that aren't directly in front of them.
 * Stellaris implements the system (details on its wiki) ostensibly in the style of Master of Orion series, but using full custom profiles with minor variations rather than combinations of basic types. Those also use different variants of dialogue (one of the extreme cases led to "Tsundere " joke).