Ghoul

Ghouls are undead creatures that serve as security guards in the Underworld. They escort the evil spirits to the Fields of Punishment. They make sounds like bats.

Percy Jackson and the Olympians

The Lightning Thief

Ghouls are seen when they surround a fake televangelist and take him to the Fields of Punishment.

The Heroes of Olympus

The Blood of Olympus

Jason Grace, Piper McLean, and Annabeth Chase meet hundreds of ghouls when they visit Ithaca. One of them is Antinous.

Monsters
Species:	Amphisbaena \| Apollo's Cattle \| Blemmyae \| Basilisk \| Carnivorous Sheep \| Centaur \| Cyclops \| Cynocephali \| Dragon \| Drakon \| Empousa \| Eurynomos \| Feather-Shooting Bird \| Fire-Breathing Horse \| Flesh-Eating Horse \| Gegeines \| Geminus \| Giant Eagle \| Giant Scorpion \| Giant Snake \| Ghoul \| Gorgon \| Gryphon \| Harpy \| Hellhound \| Hippalektryon \| Hippocampus \| Hydra \| Hyperborean Giant \| Ichthyocentaur \| Karpoi \| Katobleps \| Keres \| Khromandae \| Laistrygonian Giant \| Leucrotae \| Lycanthrope \| Makhai \| Merperson \| Myrmekes \| Nikai \| Pandai \| Pegasus \| Pit Scorpion \| Satyr \| Scythian Dracaena \| Sea Serpent \| Siren \| Strix \| Stymphalian Birds \| Tauri Sylvestres \| Telekhine \| Troglodyte \| Unicorn \| Vrykolakai \| Yale
Friendly Monsters:	Argus \| Blackjack \| Briares \| Bombilo \| Chiron \| Cottus \| Don \| Ella \| Festus \| Gleeson Hedge \| Gray \| Grover Underwood \| Guido \| Gyges \| Lysas \| Mrs. O'Leary \| Ophiotaurus \| Peaches \| Peleus \| Porkpie \| Rainbow \| Scipio \| Tyson \| Tempest \| Sssssarah
Enemy Monsters:	Antaeus \| Agrius and Oreius \| Arachne \| Cacus \| Carthaginian Serpent \| Charybdis and Scylla \| Chimera \| Chrysaor \| Clazmonian Sow \| Colchis Bulls \| Echidna \| Euryale \| Geryon \| Kampê \| Karkinos \| Kekrops \| Lamia \| Manticore \| Medusa \| Minotaur \| Nemean Lion \| Polyphemus \| Python \| Skolopendra \| Sphinx \| Stheno \| Sun Dragons \| Typhon \| Trojan Sea Monster
Neutral Monsters:	Cerberus \| Erymanthian Boar \| Gray Sisters \| Furies \| Ladon \| Orthus \| Sybaris