The reason he spelled Arceus Arkoos is because of a joke that youtuber named Mandjtv made. He has a series called Pokémon Talk, where Bulbasaur and Squirtle interview Pokémon. In one of them, Arceus comes onto the show, and they ask him about how his name is pronounced. Like is it Ar-kay-us, Ar-see-us, or Ar-key-us. But he reveals his name is pronounced: Ar-koos
