In Jewish folklore, Rahab (whose name means noise, tumult, arrogance) is a mythical sea monster or a demonic dragon of the water known as the "demonic angel of the sea." It represents the primordial abyss, comparable to Leviathan and Tiamat. Rahab later became a particular demon, inhabitant of the sea, especially associated with the Red Sea.
In the Talmud, Rahab is or was the angel of insolence and pride, responsible for shaking the waters and producing big waves; he is also responsible for the roaring of the sea.
Rahab is an Angel that resides in Rahab no Ibashyo, where he watches over one of the books of Raziel. Hearing Masaki Kuzuha's name has him reveal that he has been waiting for him, and offers him a chance to read the book and learn of his future. He tells him that there are other books as well once he takes it and that he should collect them all.
DemiKids: Light & Dark
"A gargantuan serpent with a body largely made of water. Can generate rain or snow."
Rahab has the power Stamina, which makes him rarely fazed by battle and quick to recover.