Diocletian's Scepter

This sceptor, once in the property of Emperor Diocletian of Rome, held the power to raise the dead. The wielder of the sceptor could resurrect a legion of Romans. It could only be a wielded by a child of the Underworld, and the legionaires would only follow an officer of Rome.

Before the Series
Impressed by Diocletian's career, Jason Grace and Reyna Avila Ramírez-Arellano often fantasized about visiting Diocletian's Palace in Split, to retrieve the sceptor. Because of Camp Jupiter's strict laws, Jason and Reyna knew they could never go there, but they made a pact that if one of them ever did, they meet at Diocletian's Palace.

The House of Hades
Believing it to be their best chance against Gaea's forces, Jason planned to head for Diocletian's Palace, leave Reyna a message, and retrieve Diocletian's sceptor. He visited Diocletian's Palace with Nico di Angelo. After leaving a note for Reyna near Diocletian's tomb, the god Zephyros arrives and told them that the sceptor had been taken by his master Eros long ago. Zephyros led Jason and Nico to his master to retrieve the sceptor, warning them (mostly Nico) on how to deal with the god of love. As consequence for passing on the sceptor, Cupid (Eros's Roman aspect) coerced Nico into revealing his romantic feelings for Percy Jackson, something that made Jason come to the conclusion that Cupid's wife Psyche had a point: Cupid was a monster.

Upon their arrival in Epirus, the Seven brought with them Diocletian's sceptor. Nico wielded it and reawakened the spirits of many dead Romans. He urged the spirits to attack the monsters who escaped from the Doors of Death, but they wouldn't follow a Greek demigod. Jason, as praetor of New Rome, tried to lead the spirits. But, given his recent defection to Camp Half-Blood, Jason received no loyalty from the spirits any more than Nico did. At the last minute, Jason stepped down as praetor and promoted centurion Frank Zhang to praetor. In the end, the son of Mars led the spirits to victory against the forces of Gaea.