From Halopedia, the Halo wiki
Deukalion is the Jiralhanae chieftain of the clan known as the Legion of the Corpse-Moon, named after the "corpse-moon" Soirapt, one of three natural satellites orbiting Doisac. He led the clan under the flag of the Banished during their search for a portal to the Ark buried on Reach. With his clan having been organized into a legion under the Banished, Deukalion holds the title of Legionmaster.
Joining the Banished
By July 2559, Deukalion and the Legion of the Corpse-Moon had joined the Banished. Alongside Dokab Castor of the Keepers of the One Freedom and Chieftain Ballas of the Ravaged Tusks, he reported directly to War Chief Escharum while Atriox was busy with his fight to control the Ark.
The Search for the Portal
After Escharum received a transmission from Atriox ordering him to locate and activate the Forerunner portal facility on Reach, Deukalion and the Legion of the Corpse-Moon were sent to the human colony with Castor, Ballas, and their forces. Each clan was assigned a third of the world to search, with Deukalion also taking the southeast third of the Eposz supercontinent.
The three clans searched the planet's glassed wastelands for months with little to show for it. Eventually Deukalion and Ballas began fighting over territory and resources stolen from human pioneers attempting to resettle their homeworld. Castor was able to convince the two chieftains to help him in his plan to follow a team of Spartans that had recently landed on the planet and come into contact with Banished forces. As far as Castor could tell, the UNSC was after the portal as well and they seemingly knew where to find it. All they had to do was follow them.
Deukalion and Ballas assisted Castor in his plan by using their forces to search for and draw the Spartans out. Under orders by Deukalion, the Legion of the Corpse-Moon participated in the attempted and failed defense and recapture of New Mohács, a pioneer settlement originally operated by the Viery Militia.
Deukalion has a blocky head with sunken green-gold eyes. His bony cheeks frame an almost cube-shaped muzzle containing blunt tusks etched with the names of those he has condemned to death on the inhospitable "corpse-moon" Soirapt. He has massive shoulders and is very tall, even for a Jiralhanae.
Deukalion wears a full set of ornate black power armor with a silver trim, and a matching helmet. He is known to wield a custom Type-2 gravity hammer called Black Death. During the mission to Reach, Deukalion utilized a Phantom as his personal transport.
List of appearances