In the Hero's Gravesidequest for Frog, Cyrus' ghost haunts the Northern Ruins in the Present as an invincible boss. Crono and his party are unable to harm the ghost with either techs or normal attacks. Eventually, Frog recognizes the ghost as Cyrus and tries to placate him. Cyrus, however, is enraged and the party is forced to flee. Traveling back to [[|Present|600 A.D.]], the team cleared the resident monsters out of the ruins and supplied the local carpenters with tools to repair the damaged structure. With the repair work completed, they re-enter the facility and discover Cyrus' grave. Cyrus' spirit rises and talks briefly with Frog, who successfully, yet emotionally, comforts his former mentor with the knowledge of Magus' defeat. As Cyrus transcends into the afterlife, the Masamune experiences a massive power gain, reinstating it as Frog's ultimate weapon.