OK. My final theory! Okay. Blahblah, nothingness, egg floats along, Arceus hatches. Arceus creates Universe, and with that, The Reverse World comes to be with it. Then Arceus makes AMU, who give spirit, and create Giratina, Dialga and Palkia, who create and control Time and Space. But then Giratina was banished to the Reverse World, but with the ability to control it and the ability to occasionally go in and out if needed, but this power cannot be abused. Then Dialga & Palkia create Sinnoh, on the molten ball of magma that was Earth, indeliberately creating Heatran in the process. Dialga and Palkia then made their ways, not supposed to ever meet again. Then after a long time Arceus created Rayquaza, Kyogre and Groudon who made the atmosphere, the ocean, and land. Kyogre and groudon would often feud, so Arceus gave Rayquaza the ability to calm them. Then they all went to rest as well, and Regigigas & the other Regis(multiple Regis, I think, including Gigas) broke up the supercontinent Groudon made, but Sinnoh was already by itself for D&P created it, not Groudon. Then in the end, life came to be on Earth, Mew being the first, and the one to give rise to more species.