The group's exact origins are classified and generally not well known, however it is suspected that BIO INT was somehow involved in their creation.
While the squad was extremely effective in it's missions, the higher up's decided that Omega, Xero, and Askad needed to be eliminated. This was in due part to Omega sparing civilians in their mission prior to the BIO INT mission, to which the civilians declared Bolverk squad "devil's" and open fired, killing several normal soldiers in the process. This was frowned upon, and it was decided to make two robotic version of Xero and Omega that did not suffer from such emotions. Kareleinne-08 betrayed the squad, leading to the deaths of Askad and Omega, with Kary self destructing when Omega resurrects from the XV virus. Omega gains control of himself long enough to beg Xero to kill him before the XV virus takes him over completely, Xero reluctantly carries out his last wish, and proceeds to give the remains of all three of his comrades one final burial.
It is later shown that the death's of the Bolverk squad was manipulated by an individual who would later bring about the new World Order, to which Xero, now an old man, has raised an apprentice to fight against. As his body is slowly consumed by the XV virus, Xero rushes into the fray one last time, leaving his appretince Enid to carry on his cause. Enid is the last link to Bolverk squad, being taught the ways of death of both Omega and Xero, and seems to also carry some of Kary's abilities as well.