In a multiverse all events and things will exist somewhere. That is the logic behind multiverse adherents dismissing the Anthropic Principle. The problem is that a Supreme Being is included in that set of events. Thus by multiverse logic the Supreme Being exists.
Excuse me for just jumping in here, but this is a field in which I have some interest.
Only if the SB is contained within the physics of the set of multiverse options is it (He) a necessary component. This gets very abstract, but the Many Worlds hypothesis doesn't actually require any super-set outside of the possible set of quantum mechanical universes. The Anthropic Principles, strong and weak, do not require or even infer a Supreme Being if the Many World hypothesis is adopted. Conversely, neither does MW exclude a SB, since a Level 4 Muliverse includes meta-quantum mechanical universes...