Poseidon- god of the sea. as the suitors are Odysseus's mortal antagonists, Poseidon is his divine antagonist. he despises Odysseus for blinding his son, the cyclops Polyphemus, and constantly hampers his journey home.
Cerberus is a three headed dog that guards the gates of the underworld to prevent the dead from ever leaving.
"athena, child of zeus,whose shield is thunder, if my husband burned rich thighbones of oxen to you, please protect my son." pg.45 book 4