>>12225494That's called a Temporal paradox, if I remember correctly. Arceus created Giratina so Giratina could create Arceus and so forth. Note that he doesn't -actually- create Arceus -- he just happens to exist outside of time and space, and since Arceus lives within, Giratina would be the only source for his existence.
I don't like this theorizing anymore. Now I understand why people turn to Religion.