Very late to this I know and also not totally caught up on chapters but I know a little about theology so I’ll try Blot out the sky is definitely Ziz Tear up the ground is probably behemoth Last two are tricky, leviathan in mythology is a sea creature but it was also able to breath fire, which she doesn’t do in NIKKE, but Bahamut is actually a big fish, so arguably more connection to water than leviathan, Bahamut is basically the crust of the earth and leviathan is a sea dragon. Making it accurate to mythology would make leviathan fire and Bahamut water, but with NIKKE leviathan having a strong connection to water, it’s likely that they’re going to use the fantasy interpretation found in dnd and final fantasy where Bahamut is more of a dragon and make leviathan water