| A | B |
|---|
| Percy | the main character |
| Annabeth | Athena's daughter |
| Grover | satyr who looks after Percy |
| Poseidon | Percy's dad |
| Mr. Brunner | Percy's Latin teacher |
| Mr. D | director of the camp |
| Chiron | trains heroes |
| Luke | Hermes' son |
| Zeus | head of the Olympians |
| Charon | loves silk suits, ferries people to the Underworld |
| Cerberus | loves red balls |
| Clarisse | Ares' mean daughter |
| hellhound | sent to destroy Percy |
| Luke | betrays Percy in the end |
| Gabe Ugliano | Percy's step-father |
| Mrs. Dodds | Percy's pre-algebra teacher |
| Chimera | attacks Percy in St. Louis |
| Echinda | trys to kill Percy in St. Louis as a woman |
| Ares | rides a Harley |
| master bolt | stolen from Zeus |
| helmet | stolen from Hades |
| Lotus Casino | where the team stayed for several days having fun |
| Crusty | waterbed salesman (really Procrustes) |
| Kronos | held in Tartarus |
| Percy's mom | she disappeared in a golden shimmering form |
| Minotaur | Percy tears off one of his horns |
| Aunty Em | Medusa |
| DOA Recording Studio | entrance to the Underworld |
