The four gods stuff is all over the place. Saint Beast (I think that's what it's called) has four god brothers with the names, Tsuzuki's got four gods' representations as summons (and Sohryuu's daughter Tenkou, which gives me no little amusement), Harukanaru Toki no Nakade has a very FY-ish setup, and four gods representations there.

Actually, they're even represented a little bit in the Sorcerer Hunters anime--at the very end, remember the dead city Zaha summons? The four (maybe five) big pillars of light spring up from four little statuettes--a dragon, a bird, a tiger, and something silhouetted but visible as a tortoise with snakes if you know what you're looking at.

For that matter, it's not exactly four gods related, but in X, the big circle of assorted kanji that's on Hinoto's floor has the seishi symbols in it, all twenty four of the things in proper alignment.