|“||Die in pain, mortal!||”|
–Keres, in The Demigod Files
The Keres (also known as Daemones) are battlefield spirits of famine and disease that feed on violent deaths and are polluting spirits. The Keres are daughters of the protogenos Nyx. In mythology, they were often found wandering battlefields. In later times, they were also regarded as the vengeful spirits of the dead. They live in the Underworld and had supported the Titans in the Battle of Manhattan, but didn't directly attack Olympus in the Second Olympian War.
Percy Jackson, Thalia Grace, and Nico di Angelo are ambushed by a group of Keres in the Underworld. During the battle, Percy is poisoned by one of them, when they scratch him on his exposed shoulder, putting his life in a perilous state, only being saved by Iapetus, whom Percy had told was named Bob and that they were friends (which is probably why Iapetus saved him).
During the battle Percy describes them as part humanoid females, part bats; they are pug-nosed and have furry faces, fangs, bulging eyes, shriveled arms, claws, leathery wings, and stubby bowed legs.
- Keres feed on death, which means their power increases when people die.
- They have deadly poison that only the power of a god, Titan, or similar being can heal.
- Some myths list Akhlys as possibly being one of the Keres.