I have a realm with a bunch of different NPC's and creatures. I would like them all to attack the player.

I know about

B

SetAttackActorOnSight() and werewolf faction but I want even werewolfs to attack him.

Is there say a way to set a trigger that any actor linked to it will attack the player or if not in range become his enemy, when it is tripped ?

You can include all of them in a faction that is enemy of player faction and make her aggresive (not very aggresive, only aggresive). This way you could also make them less hostile to the player if you need to, by just making their faction neutral to the player faction.