How many monsters have Percy killed?

In the Percy Jackson series, Percy has killed a number of monsters, including:

- The Minotaur

- The Hydra

- The Nemean Lion

- The Erymanthian Boar

- The Stymphalian Birds

- The Cerberus

- The Gorgons

- The Lotus Eaters

- The Sirens

- The Scylla

- The Charybdis

- The Echidna

- The Ophiotaurus

- The Campe

- The Kronos

- The Oceanus