The Ouroboros is first visited in Kaocho and first heard of in Passaj as ruins in which the Kaocho reign has settled itself. The party is told that the Alchemy Forge in Pasaaj can only be fully activated by using the Sol Mask that is housed in the labyrinth's interior.
Although the Ouroboros is visited the first time the party goes to Kaocho, he party cannot retrieve the Sol Mask at this time, as they lack the proper tools at this time to do so. Only much later after Amiti is recruited into the party as a full fledged member, can the party solve the labyrinth as they need the Insight Psynergy that only Amiti can use.
In actual gameplay, the Ouroboros is not as difficult as the characters in the game claim. This is largely because the dungeon itself is not difficult, but rather the real problem comes in that to solve it, one needs to find the true entrance to the Ouroboros which cannot be detected without Amiti. After that, the dungeon is very straightforward, the few detours one can make are largelly for treasures and even then, they are simple and one can retake their main path without much delay. Mostly the Move, Whirlwind and Fireball Psynergies are needed to solve the dungeon.
The Ouroboros is known to contain following Monster types:
The Ouroboros is a recurrent symbol in alchemy, that is of a snake biting its own tail. It symbolizes infinity and eternal cycles such as the ongoing cycle of life and death, from which alchemists sought to break.