An XM is created through a somewhat complicated process - an alien larva is allowed to mature to a certain point, and then encased in armor designed to weaken and control it. The more powerful units require longer periods of time to be grown, the most extreme example of which is Korol. One of the first XMs to have been born, Korol was allowed to mature for 50 years, until it reached the peak of its maturation. Because of this, its restraining armor is the thickest and most powerful of any XM, barely suppressing its enormous power.
The unit was originally assigned to Pomfret Akumu, captain of the battlecruiser "Patient One", which was assigned to an area of space which the Arbalest passed through on its route back to Earth. After several battles with Alexander Kanbara and his Kerykeion Mark III, the captain decided to go out himself, and took Korol out without authorization. Devastatingly powerful, Korol pulverized the then-incomplete Mark III, but was forced to retreat before he could finish the battle by the arrival of reinforcements. For taking the Korol out without authorization, Pomfret was demoted, and the unit was given to a new pilot.
It soon became apparent that Korol had originally been assigned to Pomfret for a reason - only he could properly control the beast. When Alex returned with his now-completed Mark III, the tables were turned - after three more fights, Korol was defeated. The crippled unit was then destroyed as Pomfret returned.
"The Korol is useless without a pilot skilled enough to work with it. This is not treason...it's natural selection."
Only one Korol was ever produced, due to the long maturation time. Its primary ranged armaments consist of a shock cannon on its right shoulder, which fires a dark red bead of compressed energy, as well as a pulse rifle on its back. Its armor is nearly impregnable, but its speed is diminished greatly as a result of its heavy restraining. This lack of speed was capitalized on in Alex's subsequent fights with the Korol, as his Mark III was drastically faster and more agile.
The Korol's clawed toes allow it to grip any surface, while its thick joints give it extreme physical strength. Properly used, it can take on an army.
For melee purposes, the Korol carries a "Stella" graviton axe, a heavy weapon mounted with thrusters on its back to further increase its already immense crushing power. A single strike from the axe shattered the incomplete Mark III's Buster Sword.