A) He stores it in Gate of Babylon bro, same place he puts all his shit. B) Nasu. Or maybe because Ea (the sword) is the sword that "split apart heaven and earth" and created the Earth or whatever happened in Nasuland, and since Enki is important or whatever in Enuma Elish (I'm not sure on this lololol) he calls it that. I dunno. Nasu, man, how does it work?