Two Sides, Same Coin
Dalia can transfer one of her two souls into her weapon, effectively making it holy or unholy. While holy, it can wound demons and other creatures harmed by holy artifacts as though they are human and while unholy it can wound gods and angels the same way. While one of her souls is in her weapon, Dalia can only benefit from the part of the Two Sides, Same Coin passive that she keeps in her own body (such as counting as a god when it would benefit her but not being able to count as a demon, etc.).