Up until recently, Ankh had assumed that his body had simply broken down into Cell Medals when he was sealed within the First OOO. However, the body had actually maintained its integrity. It remained dormant for 800 years until it was discovered by Kosei Kougami, who awakened it when he removed one of its Core Medals (the Condor Medal he would later give to Eiji). Ankh and his body now exist as two separate entities, and it is presumed that the weaker of the two would be consumed should the two be reunited back into one. As a result, Ankh (Lost) is consumed by the desire to become a whole being and he thus supports Kazari and Dr. Maki to achieve that single-minded goal. He disguises himself as a young boy to avoid detection while developing mentally over time.
After tutoring from Kazari and the other Greeed, Ankh (Lost) created the Shamo Yummy in a complex and very successful plan to reabsorb his other half while his guard was down. Despite fully absorbing Ankh, Ankh (Lost) has still not been able to fully regenerate due to Ankh having secretly given Hina a Taka Medal at the last second. Their fusion is also incomplete as Ankh (Lost) could sense his other self still defying him on a subconscious level. Though that issue seemed to be resolved, Ankh (Lost) battles OOO in Putotyra Combo. However, OOO Putotyra Combo goes berserk and shatters a full set of red Core Medals, destroying Ankh (Lost) while restoring Ankh's consciousness over the body. However because he has six Core Medals, Ankh is unable to maintain it as he modeled his human form after Shingo's possessed state.
Ankh (Lost) has the personality of a lost and confused child yearning to be complete, driven to absorb his right arm. Over time, Ankh (Lost) became more assertive and gained advanced mental capacity, much like the original Ankh. This one also refers to himself with the humble pronoun "Boku", as opposed to the Ankh's boastful "Ore".
In his incomplete form, Ankh (Lost) can fly using his left wing, through which he can project an energy shot. He can send the flames from his left forearm to the enemy and execute an attack similar to the Kujaku Arms' Tajadol Feather Barrage, as well as the Prominence Drop Scanning Charge attack. After absorbing the Condor medal that Uva had stolen from OOO, Ankh (Lost) has shown the ability to knock away Gamel with his wing while in human form, as well as conjure massive red tornadoes that can be used to teleport the other Greeed,
Yummy created by Ankh (Lost) first come out of a giant egg as a White Yummy and feed off their hosts' desire before maturing in a burst of energy. Some of them function to attack people and rob them of an attribute which they feed to their host, similar to a mother bird feeding her chicks. When Ankh (Lost) is destroyed, the original Ankh regains his ability to create Yummy.