Hades first uses his chariot to try and recapture Percy Jackson after he escapes from his cell in the dungeon. Hades tries to attack Percy but the latter destroys his soldiers and tackles him off of his chariot.
After Nico di Angelo convinces his father that he should help the Olympians, Hades, along with his wife, Persephone, and mother-in-law, Demeter, appears on Fifth Avenue to confront his father. Kronos' army cowers from him, as Hades is flanked by un-dead soldiers and is wearing his Helm of Darkness. Only Kronos' power and their fear of it stops them breaking ranks and running for their lives.
It is described by Percy as an obsidian and gold chariot, decorated with depictions of painful deaths. The horses are made of 'living shadows', and who have eyes and manes that smolder with fire.