The Yamatano Orochi is an enemy in the Dawn of Souls and succeeding versions of the original Final Fantasy. It is a very rare enemy, found in the deepest levels (B31 - B39) of the Whisperwind Cove in the levels resembling Mount Gulg, and in the levels resembling the Flying Fortress.
It often uses Blaze on the party, inflicting a decent amount of damage. Otherwise, despite its high HP, it should be of no threat to the party.
Yamata no Orochi (八岐の大蛇?, lit. Eight-branched giant snake) translated as the Eight-Forked Serpent in English, is a legendary 8-headed and 8-tailed Japanese dragon that was slain by the Shinto storm-god Susanoo.