When the Covenant Empire betrayed the Sangheili and the Great Schism broke out, Resa and his squad joined the Covenant separatists. Following the outbreak of the Great Schism, Resa became lost and disillusioned because of his former belief in the Great Schism and he became devoted with hunting down and slaughtering the Jiralhanae and those affiliated with them.
He led many missions including an armory on the fourth moon of Victor's Truth and the last of the Cheiftain Tartarus' crew onboard of the Rapid Conversion. Over time, however, his personal war with the Jiralhanae began to wear off on his squad.
Meeting Atriox and Death
Eventually, Resa led his squad onboard Elegy's Lament. He and his men activated their Active camouflage and caught many Jiralhanae off-guard. However, this ship had not belonged to the Covenant, but rather the Banished. Onboard at the same moment, was the Banished leader, the feared Jiralhanae Warlord Atriox. Atriox had smelled their scent long before they reached the vessel's bridge. When the assassins arrived, Atriox invited them to show themselves. Instead of trying to kill them, Atriox extended an invitation to join the Banished. Resa refused, deeming Atriox a "Betrayer". However, his subordinates turned on Resa and they drove their Bloodblades through his chest, believing he had become disillusioned with his quest for vengeance and they joined the Banished.
Halo: Tales from Slipspace (First Appearance)