(RPG elements are optional, you know. )

Jenny: "Why not ask you God to help you in the battle, PK?"

PK: "...Never thought about that.
"Probably wouldn't be at full power unless this universe is confirmed to be Christian-based."

Yoshiro: "But he'll still be powerful, right?"

PK: "Right.
"Besides, God's not a weapon. I can't just go use him in battle. I need to pray to him first."

EXPOSITION: PK has been a Christian since he was still a human, which is really long time ago. The fact that he stayed a Christian no matter what is a miracle of itself, as well as proof he still has the "Gift of Faith" like his real world equivalent me.

In case you're wondering, when PK first warped outside his birth world, a fragment of God found its way into PK's heart.

So, in a way, his God's with him whenever he goes.

He personally doesn't mind, though, as according to Christian believes, God's eternal, and thus, is not really bound by time.

The more a world's properly based upon Christian beliefs, the more powerful He becomes, as he could team up with said world's equivalent of Him.