Harley is an eight-year-old Greek demigod, a son of Hephaestus, and a camper at Camp Half-Blood.

The Heroes of Olympus

The Lost Hero


Hephaestus, his father

Harley is first introduced when Leo Valdez visits the forges for the first time. The youngest member of the Hephaestus cabin, he is seen working along with his siblings to catch the bronze dragon, which is later named Festus (Latin for Happy) by Leo. Harley is affected by the so-called "Curse of Cabin Nine" at the time, which makes everything they build go haywire. At the only time he is seen, he is depressed because of the curse. He has many siblings, including Leo, Nyssa, Christopher, and Jake Mason. Leo comments that all of the kids in this cabin look different, saying, "You'd never think, 'Hey! It's the Hephaestus bunch!'"

The Trials of Apollo

The Hidden Oracle

Harley is first seen explaining the rules of the three legged death race, which everyone is annoyed about. However, nobody dared to protest, because the race was Harley's idea and they did not want to disappoint him. The following day he started the race.

When Austin and Kayla went missing during the race, he became very upset. He cheered up when Apollo gave him advice for the home-beacon he was trying to build in order to help Leo. In return, he gave the former god a combat ukulele, which he had made himself.

He helped defending the camp from Nero. Harley was very mad at Leo when he returned, and he even punched him. But after that, he gave Leo a hug, cried, and ran away.



Leo, his half-brother

In the Lost Hero, he was described as beat-up and depressed, probably because of carrying the weight Curse of Cabin Nine. Harley is also very strong, as he works on the forges. Leo describes him by saying that "even little Harley looks like he could probably go six rounds with Chuck Norris without breaking a sweat". Harley's hands are described as being large and calloused.

In The Hidden Oracle, Harley is said to be "scarily buff for for an eight-year-old" and to have an infectious smile that can lift the mood of people at Camp Half-Blood. Apollo described him as a cute little pipsqueak. He is also said to have a mad gleam in his eyes that resembles Hephaestus when he invents a new automaton.


As a child of Hepheastus, he has the following abilities:

  • He is an expert builder.
  • He is an expert mechanic.
  • Technokinesis: As a son of Hephaestus, he can control machines.
    • He can sense machines, mechanics, or metal.
    • He can identify machinery type and use by touch.
    • He can sense faults in metal ore.
  • He can find and sense traps in the ground.


  • It is hinted that Harley is named after "Harley Davidson," the popular motorcycle company.
  • He is technically the youngest demigod to appear at a camp in either series.
    • Annabeth Chase was seven when she came to Camp Half-Blood but debuted at age twelve. 
    • Jason Grace was two when he arrived at Camp Jupiter but debuted at age fifteen. 
The Heroes of Olympus
Core Series: The Lost Hero | The Son of Neptune | The Mark of Athena | The House of Hades | The Blood of Olympus
Main Characters: Jason Grace | Piper McLean | Leo Valdez | Percy Jackson | Frank Zhang | Hazel Levesque | Annabeth Chase | Reyna Avila Ramírez-Arellano | Nico di Angelo | Gleeson Hedge
Minor Characters: Rachel Elizabeth Dare | Thalia Grace | Octavian | Fleecy | Dakota | Ella | Tyson | Mrs. O'Leary | Arion | Hylla | Bob | Calypso
Olympian Gods: Zeus | Hera | Poseidon | Hades | Ares | Demeter | Athena | Apollo | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus
Minor Gods: Achelous | Aeolus | Asclepius | Boreas | Eurus | Hecate | Iris | Hypnos | Keto | Khione | Kymopoleia | Mithras | Nemesis | Nike | Notus | Phorcys | Serapis | Thanatos | Triptolemus | Zephyros
Roman Gods: Jupiter | Juno | Neptune | Pluto | Mars | Minerva | Ceres | Lupa | Bellona | Fortuna | Janus | Terminus | Vulcan | Mercury | Pomona | Aquilon | Hercules | Cupid | Auster | Favonius | Letus | Victoria | Orcus
Giants: Enceladus | Porphyrion | Alcyoneus | Polybotes | Ephialtes | Otis | Damasen | Clytius | Mimas | Orion | Hippolytus | Thoon | Periboia
Undead: Medea | Midas | Lityerses | Gray | Phineas | Otrera | Echo | Narcissus | Sciron | Pasiphaë
Primordial Gods: Gaea | Tartarus | Ourae | Nyx | Chaos | Ouranos | Akhlys | Erebos | Hemera | Elpis | Spes
Companion Books: Percy Jackson and the Olympians | Demigods and Monsters | The Ultimate Guide | The Demigod Files | The Demigod Diaries | The Son of Sobek | The Singer of Apollo | The Staff of Serapis | Percy Jackson's Greek Gods | Percy Jackson's Greek Heroes | The Crown of Ptolemy | Demigods & Magicians | Demigods of Olympus
The Trials of Apollo
Core Series: The Hidden Oracle | The Dark Prophecy | The Burning Maze | The Tyrant's Tomb
Main Characters: Apollo/Lester Papadopolous | Meg McCaffrey | Peaches | Leo Valdez | Calypso | Grover Underwood | Piper McLean | Reyna Ramírez-Arellano
Minor Characters: Percy Jackson | Sally Jackson | Nico di Angelo | Will Solace | Chiron | Rachel Elizabeth Dare | Thalia Grace | Mrs. O'Leary | Festus | Cade | Mikey | Kayla Knowles | Austin Lake | Harley | Connor Stoll | Miranda Gardiner | Cecil Markowitz | Ellis Wakefield | Sherman Yang | Damien White | Malcolm Pace | Paolo Montes | Germani | Agamethus | Hemithea | Josephine | Georgina | Lityerses | Olujime | Hunter Kowalski | Sssssarah | Trophonius | Prickly Pear | Aloe Vera | Joshua | Gleeson Hedge | Mellie | Chuck Hedge | Naevius Sutorius Macro | Incitatus | Crest | Tristan McLean | Medea | Jason Grace | Herophile | Lavinia
Olympian Gods: Zeus | Hera | Poseidon | Demeter | Ares | Athena | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus | Hades
Minor Gods: Nero | Iris | Britomartis | Commodus | Styx | Caligula
Titans: Rhea | Leto | Mnemosyne | Helios
Monsters and Magical Creatures: Python | Nosoi | Karpoi | Palikos | Myrmeke | Colossus Neronis | Blemmyae | Gryphon | Carthaginian Serpent | Scythian Dracaena | Cynocephali | Centaur | Cyclops | Yale | Satyr/Faun | Dryad | Strix | Dragon | Pandai | Eurynomoi
Related Content: Rick Riordan | Percy Jackson and the Olympians | The Heroes of Olympus | Demigods & Magicians | Camp Half-Blood Confidential