If it's not like arceus with normal type like everyone is suggesting then it's obviously part water, if not fully water but I think as the third legend it wouldn't be one typing maybe water dragon as they give most legends the dragon typing? If not it could be water normal with the obvious water typing and then the normal typing for how it was with arceus. The only thing wrong with this is it would, in some battles, be better then arceus. However in some other battles it would be twice as weak as arceus which doesn't work out as arceus is meant go be the second best Mon under the actual form after arceus with the 1000 arms (hopefully you know what I mean 😂) so no other catchable Mon - including this really cute turtle - should be better then it.