Percy Jackson is the protagonist and point-of-view character of The Sea of Monsters. Almost a year has passed since the end of The Lightning Thief, and Percy’s “normal” life away from camp reflects how he lives in both the mortal world and the world of the Greek gods. Attending a regular school, if one for eccentric/troubled kids, calls to Percy’s mortal side and how his non-godly parent is a big part of his life. Percy’s excitement to return to Camp Half Blood for the summer juxtaposes his mortal nature, and the fact he carries his pen-sword Riptide with him wherever he goes shows how Percy can never completely live as a normal mortal.

Percy’s life is also a dichotomy in terms of his demigod nature. As a child of Poseidon, one of the big three gods, Percy stands apart from the other kids at Camp Half Blood. He is more powerful than the other campers and, following his retrieval of Zeus’s lightning bolt in the previous book, is seen as a hero, despite being a prohibited child of the big-three gods. When Poseidon claims Tyson as his son in The Sea of Monsters, Percy feels betrayed.