Ultimus's History
Ard-Con was a Kree Eternal, a sub-race created a long time ago as part of the Celestials' experiments.
He possibly encountered Odin, claiming that that name brought back distant memories, but also thought that Odin lived no more.
Along with other Kree Eternals, Ard-Con journeyed through space and traveled to Earth 4000 years ago. After being mistaken for Gods by the Celts, all Kree Eternals soon left, save for Ard-Con who lived there for a millennium, but was soon imprisoned by Tantalus.
Liberation
Ard-Con awakened due to the vibration caused by Thor after striking the ground with Mjolnir in order to turn himself back into Donald Blake, after arriving in Charring Cross, London.
Freeing himself from his rock prison, the Demon Druid soon wrecked the street and blasted Thor unconscious while refusing to speak to him. He then resumed his mission, which was intending to find rest once more.
In his course, he was assaulted by the British Army then once again by Thor in the district of Esher on the Portmouth road, and one more time at Salisbury Plain in Wiltshire county, next to Stonehenge.
After Thor was able to stun Ard-Con for a minute, Scotland Yard Inspector Prichard intervened, noting that the Demon Druid was merely trying to reach a portal located at Stonehenge so he could escape Earth. Now free of further attacks, Ard-Con used Stonehenge, his transportation pad, to depart Earth.
Return to Earth
Unable to reach his people, Ard-Con later returned at Arthur's Seat, Edinburgh, via a portal created from two tourists there, and reiterated his trick on the mutant Meggan. The intervention of Shadowcat via her phasing powers forced him to retreat, thus freeing both tourists and Meggan as well as allowing Rachel to gather some of Ard-Con's knowledge about his people's place in the process.
He soon broke into Darkmoor Nuclear Research Facility where he recreated a nuclear facsimile of Stonehenge as part of his plan to power a portal so he could return to his own people. As Excalibur intervened, Shadowcat understood Ard-Con's intent, and sent Phoenix to stop Captain Britain from engaging in a fight while buying some time for her to use Widget to open him a portal to his kind and, at the same time, connect with him via Rachel's telepathy so she could apologize for their behavior.
Return to the Kree
The portal successfully led him home, but Ard-Con soon discovered that his people were all gone. He then renamed himself Ultimus and was soon found by the Supreme Intelligence, who revealed to him his status as the last Kree Eternal. Ultimus was then designated by Supremor as a member of the Kree Starforce along with Shatterax, Korath the Pursuer[6], Captain Atlas and Dr. Minerva.
They were sent to take down the Avengers who had infiltrated Kree-Lar, with Ultimus taking on Hercules and besting him as well. After a brawl, they had the Avengers surrounded.
However, the co-rulers of the Kree, Ael-Dan and Dar-Benn, soon intervened and thanked the Starforce for their capture, then decided to execute both teams by locking them into a force field. At that moment, the two Kree emperors were killed by Deathbird, thus allowing the Supreme Intelligence to regain control of the Kree Empire. He then decided to send the Starforce to Chandilar, while being led by Ronan, as a form of retaliation against his attempted assassination by the Shi'ar.
After teleporting themselves into the Shi'ar palace, Ultimus attacked Lilandra and dispatched Earthquake, but was distracted by Starfox long enough for Lilandra to shoot the Kree in the back.
All Starforce members were soon captured and then sentenced to death by the Shi'ar, which resulted in opposition from the Avengers. The battle soon came to a halt when counselor Araki was revealed to have been replaced by a Skrull. Lilandra released Ultimus in order for him to report the Skrulls' machinations, while informing him of the disappearance of a Nega-Bomb which was originally sent to the Kree.
The Starforce then escorted Lilandra, along with the Imperial Guard, as she came to claim Hala and all Kree territory as part of the Shi'ar Empire, while making Deathbird the Shi'ar viceroy and Kree ruler, and the Starforce her Imperial Guard. Under Deathbird's lead, they attacked Quasar and his allies for their intrusion into what was now Shi'ar space, thus forcing them to retreat.
When the Kree Empire later regained its autonomy, all Starforce members were branded as defectors. His current fate is unknown.
