driver given to Nico by Hades as a gift. Jules Albert acts as Nico's chauffeur and is used by Nico in The Blood of Olympus to transport himself, Leila and Dakota to Camp Half-Blood since none of them know how to drive. Greco-Roman creatures Amphisbaena - A snake with another snake head at its end. In The Tower of Nero, Apollo encounters one in the subway. When he grabs it, it recites part of the Terza Rima prophecy before being killed by the Gaul Luguselwa. Apollo's Cattle – The sacred cattle herd of Apollo. In The Battle of the Labyrinth, Apollo's Cattle were seen at the Triple G Ranch under Geryon's care since Apollo never has time to take care of them. Apollo was unaware that he was using some of the cattle for meat and feeding them to the monsters that work for Kronos. Although Apollo didn't have any cattle in actual Greek mythology, these cattle are based on the Cattle of Helios. Arai – Winged female daemons who inhabit Tartarus. They are similar to the Furies, but their number is not limited to three, and they are under control of Nyx instead of Hades. The spirits carry the grudge of anyone whom their killer have wronged; when Percy kills some of them, they release the grudges of Kampê's death by crushing and Calypso's isolation in Ogygia. Arion – A horse born to Neptune and Ceres, making him Percy's half-brother. He appears in The Son of Neptune where Hazel frees him from the Amazons. He is described as having a tan coat with a black mane and tail. He is a free spirit and seems to have a bad temper, being known to curse when his abilities are challenged. After Hazel frees him, Arion becomes her steed, although he is known to reluctantly let others ride him at Hazel's request. Aristophanes - A cat that lives in the bookstore in New Rome. In The Tyrant's Tomb, Tarquin tries to interrogate him on where the Sibylline Books are. Automaton – Highly developed robots with intricate circuitry that makes them hard to fix. Most are made out of steel, but some are made out of celestial bronze or other materials. In the Percy Jackson & the Olympians series, Annabeth discovers that many statues in Manhattan are actually automatons created by Daedalus, an army that could either defend or attack Olympus. Argentum