Rakkus was a member of the Acolytes and participated in the battle with the High Evolutionary.
When Rakkus was first seen he was placed with a shepherd named Fydor (a close friend of Bova) by Exodus, who was seeking to draw out the High Evolutionary.
Under Exodus' direction, the Rakkus-controlled Fydor slowly poisoned Bova. As she became progressively more ill, he cared for her and provided companionship, though he continued to poison her. It is unclear whether Fydor was even aware of what he was doing whether his mind was completely submerged under Rakkus' own personality, whether Fydor was helpless to stop himself from poisoning her despite being aware of it, or whether Rakkus only influenced Fydor, causing him to poison her, but preventing him from realizing what he had done.
Quicksilver and Crystal came to visit the ailing Bova and soon after encountered the High Evolutionary and his Animutants, a new group of New Men, who assumed them to be trespassers on the mountain. Their struggle drew the attention of the High Evolutionary, and when Bova noticed that Pietro and Crystal were gone, the Rakkus-controlled Fydor, who had been watching the struggle told her that they had gone to the village on a minor errand.
When Pietro and Crystal failed to quickly return, Fydor assured Bova that they were merely delayed by a storm and that they could take care of themselves. Some time later Fydor fed Bova some broth. Meanwhile, Quicksilver told the High Evolutionary of Bova's illness. The Evolutionary and the Animutants accompanied Pietro and Crystal back to Bova's cottage, where he quickly determined that her illness was not organic, but that she had been poisoned. An image of Exodus then appeared, revealing his responsibility and motivation before directing Rakkus to transform Fydor into monstrous forms. Rakkus/Fydor then released an explosion that leveled Bova's cottage and the surrounding landscape.
The High Evolutionary formed a force bubble that shielded himself, Crystal, Quicksilver, and Bova from the explosion.
Rakkus slaughtered a pair of New Men who approached the site of the explosion, and then assaulted the High Evolutionary, while Bova tried to reach her friend Fydor within Rakkus. After standing up to the combined assaults of Quicksilver, Crystal, and the High Evolutionary, Rakkus was stunned by a more potent blast from the Evolutionary. When Bova approached him again, Rakkus grabbed her and would have slain her, but the High Evolutionary focused his power and fired a blast that slew Rakkus. As he died, Fydor returned to normal, telling Bova that he had not been the one to hurt her. She wept for her lost friend.
Rakkus' current status is unknown. And it is unknown if Rakkus retained or lost his mutant abilities during the M-Day.