Quetzalcoatls, keepers of the dead, until humans matured and no longer needed them. They went underground along with a few humans who joined them. Afterwards, Asuna goes to her hideout to find another mysterious boy who looks like Shun standing on the ledge. Just then, a group of armed men called the Arch Angels appear, and attack both of them. The mysterious boy hides in the underground entrance with Asuna, and the two proceed further into the cave when the cave's entrance is bombed. The two meet a Quetzalcoatl who has apparently lost its physical senses and attacks the boy. He refuses to kill the gatekeeper, giving Asuna his clavis, a crystal, and fights back. The Arch Angels interfere, killing the gatekeeper. The Arch Angel commander captures Asuna and uses the clavis to open a gateway to Agartha. The commander and Asuna enter the gateway followed by the boy. Once inside the commander reveals himself to be Morisaki and the boy also reveals himself to be Shin, Shun's younger brother. Morisaki tells Shin that all he wants is to bring back his late wife from the dead. Shin leaves Asuna and Morisaki. Morisaki tells Asuna that she can go back but she decides to accompany him. They both go into the realm via an underwater entrance. Once inside, they journey to the Gate of Life and Death which can bring the souls of people back from the dead, along with Mimi (who had sneaked in inside Asuna's backpack). Upon arriving in his village, Shin is told he failed his mission to retrieve the clavis, because Asuna has unknowingly returned with a fragment of one. Shin re-embarks to stop Asuna and Morisaki from wreaking havoc in Agartha. Along the way, Asuna is kidnapped by a race of monsters called the Izoku. She awakens in a closed area and meets a young girl named Manna; they both try to escape but are not able to. The day begins to darken and the Izoku begin to appear, but they can only move in the shadows. In their escape attempt they encounter Shin, who helps them but is wounded by an Izoku during the escape. Morisaki finds Asuna and Manna down the river as well as Shin with the help of Mimi. Shin tries to retrieve the clavis crystal fragment that belongs to Asuna. However, he is too weak to put up a fight