Acht is an 18-year-old antagonist with silver-white hair cropped at his ears, piercing blue eyes, and a face often concealed behind a mask. Partially transformed by the Cagaster virus, his hybrid form merges human and insectoid traits, including wings, rib-mounted pincer legs, and pallid skin. Clad in desert garb, he later abandons his hat but retains white garments to obscure his mutations. A violent and cannibalistic force, his actions are fueled by self-loathing and a fractured identity. Genetically manipulated through human experimentation to serve as Ilie’s uncle or brother, he wavers between attacking her and restrained recognition, exposing a fractured kinship. Driven by vengeance, he works for Adham’s forces to capture Ilie, aiming to convert Trade City E-05 into a containment zone known as the insect cage. He ambushes the protagonists after a man claiming to be Ilie’s father triggers their escape, and he ensures Ilie remains imprisoned in E-07, thwarting rescue efforts during the main tower infiltration. In combat, his hybrid physiology grants lethal speed, crushing strength, and paralyzing venom, though his internal conflict breeds self-destructive impulses. A redemptive sacrifice, ignited by Kidow’s acknowledgment of his lingering humanity, allows him to transcend his antagonist role.