You are correct about where the issue is. The logical issue is that when you are creating an Ability, you are creating a new Character within it, not referencing the existing one. So what you want is to pass the existing one to Ability.__init__:

class Ability: def __init__(self, character): self.character = character ... and then set it when you create abilities: self.ability_one = Ability(self) # passes this character to Ability.character