Player vs Player
Whenever a player character is targeted by another player character for an action, the targeted player character has the option to treat the action as hostile—even if the action would be beneficial to them.
When this occurs, the attacking player rolls the usual, appropriate dice pool for their action. The defending player rolls to defend against the hostile action, picking a dice pool based on how their character would defend against the attack. Whoever rolls the highest number of successes wins. The defender wins on ties. If the winner was the attacking player character, they resolve the roll as normal. If the defender wins, the attacker fails their roll and receives Complications.
If a player character’s attack has multiple targets, and another player character is targeted by the attack, the player character defends against the attack as normal. The attacker does not receive Complications unless they fail their roll through normal means, or they receive Complications from an ability.
You can never perform actions against other player characters with the intention of influencing their actions or decisions. Players have complete agency when it comes to the decisions their characters make—unless they are being controlled, or they’re confused. You also can’t affect a player character’s disposition, because they do not have one.
When a player character is being directly controlled by the game master (GM) through the Controlled or Confused statuses, they are treated as a non-player character (NPC) in all respects, and so do not follow player versus player rules.