Spider Demon (Son)

He had the body of an enormous spider topped with a human face. That face carried the same red dots, pale skin, and white hair shared by the family and modeled after Rui, though his eyes were unusual: dark red scleras around blue irises and black pupils, with one eye opened wide over a tiny pupil and the other narrowed over a large, dilated one.

His spider half was furred like a tarantula, purple in color, with orange bands running along the legs and orange marks across the thorax. Spinnerets at his rear nearly always trailed a strand of silk, which he used to hang upside down.

He was cruel and took pleasure in others' pain. In Mother's recollections he openly relished the beatings she endured from Rui and the false father, addressing them politely as his parents and clearly enjoying his part in the charade. Like the father figure he obeyed Rui without protest, and he hated humans, having converted countless people into spiders and lorded over them once their minds were gone.

His pride and mockery showed most clearly when he toyed with Zenitsu Agatsuma over the boy's coming transformation. He was boastful and quick to insult, dismissing his opponent's single technique and bristling at the idea of losing to someone he thought beneath him. That arrogance collapsed into panic once Zenitsu's true power emerged, sending him scrambling back toward his house.

He ranked as a fairly powerful demon and a real danger on Mount Natagumo, responsible for transforming many helpless Slayers into spider hybrids. He nearly killed Zenitsu, a cowardly but gifted fighter, and his unusual body paired with his range of poisons made him a tough opponent. Of all the family he carried the most spider traits, with eight legs, an abdomen, and a thorax, and he could spin silk strong enough to suspend a small house and many captives above a clearing.

His central gift was the generation and control of poison. One venom slowly converted a human into a spider creature over roughly half an hour, stripping away their intellect and leaving them obedient to him, a change Shinobu Kocho later reversed through medicine and a regular antidote. His other venom was a corrosive purple acid he spat from his mouth, capable of burning a hole clean through a tree. His signature attack was a spitting venom strike that dissolved whatever it struck. In the end Zenitsu's enhanced Thunderclap and Flash, Sixfold reached him before he could flee and severed his neck in Chapter 34.