Iapetus

Iapetus-He is the brother of Kronos and the father of Atlas. His name means The Piecer, because that's what he likes to do to his enemies, as said by Thalia in The Sword of Hades in The Demigod Files. He battles Percy, and Percy grabs Iapetus with the little strength he had in his injured arm (he had been hurt in an earlier battle) and pulled himself and Iapetus in the River Lethe, which makes you forget everything about yourself. As said by Nico, 'You'll be like a newborn baby.' Percy, since he doesn't get wet thanks to his father being Poseidon, remembered who he was, but Iapetus did not. When he sees Percy, Nico, and Thalia, he smiles at them and asks, "Who am I?", and Percy says he is their friend Bob. When he sees Percy's shoulder wound, he says "Owie" and heals it with a touch.