Mamushi

Because he sprang from Bug, Mamushi mirrors him closely, taking the form of a stunted, aged figure with gaps where teeth should be and a white beard grown to great length. His garments, shared in style with the other awakened trees, are fashioned from Claw Marks: a studded strip bridges his nose, and a long studded tabard hangs from him beneath an outsized collar of indigo fur.

Though he otherwise passes for human, a pair of purple Rinnegan sit in his eyes, and his three-toed feet echo those of the Claw Grimes.

Standing among the sentient God Trees, Mamushi ranks as a monster whose might eclipses even his maker, Code. He travels by passing through Claw Marks and drifts freely through the air under his own power. His signature gift is endless self-copying: unlike the ordinary Fission Technique, his Division spawns as many duplicates as he pleases with no loss of chakra or strength across them. He can also breathe out fierce streams of Fire Release.

Physically he is remarkably fast and strong, once catching Boruto off guard and hurling him into a cliff hard enough to shatter part of it, and he can reshape his arms into an enormous jaw resembling a meat-eating flower. As a sensor he perceives when anyone watches him and can briefly borrow their point of view, as when he caught Ada observing him through her Senrigan, and he can likewise mask his own chakra from detection.

Mamushi enters the story when Boruto trails Code into the dimension holding his imprisoned Ten-Tails, only to find the beast gone. He materializes moments later, startling Code, since the tree that had once been Bug still stood close by. Boruto clarifies that this newcomer is no longer the man Bug but an evolved Human God Tree reshaped by Code's tampering. Branding Boruto an Otsutsuki, Mamushi attacks with intent to devour him, and three more evolved trees emerge, their leader explaining that the group has awakened to self-awareness. A detached, largely silent being, Mamushi speaks only when he sees cause and carries a streak of cruelty, happy to mock another's suffering even when the victim is Code himself, though he takes care never to provoke the leader, Jura.

Retreating to their lair beneath a colossal tree, the trees puzzle over their emerging identities and unfamiliar emotions. When Jura urges them to follow their cravings and pick prey, Mamushi senses Ada spying through her Senrigan and announces her as his chosen target, convinced her superior genes would advance the Human God Trees. He later helps revive the fallen Hidari, warning Jura to act before the Thorn Soul Bulb decays, and takes part in the birth of a new sentient tree, Ryu. He laughs openly when Code, captured and defiant, loses a hand attacking Jura.

His own campaign begins once he grasps why Ada draws him. Slipping into Konoha with his chakra erased and his Division active, he questions civilians for her whereabouts and turns to killing when they cannot answer. Boruto intercepts him, and though the copies swarm and scorch him with fire, Boruto's Kama absorbs the flames and lets him cut the duplicates down. Realizing they are somehow being tracked, the survivors multiply and scatter, only to be met by Team 10, Himawari, and Kawaki. Mamushi spawns into the hundreds yet still spares random bystanders, cornering the Fire Daimyo's advisor Kobu, unaware the man is being puppeted by Inojin.

The hunt escalates into the thousands after an attempt to wipe the copies out fails when Sarada collapses from straining her Mangekyo Sharingan. The end arrives when Inojin, deducing that the copies share a single mind, seizes control of them and steers Daemon's reflected killing intent into destroying their eyes, the very source of their division. The horde crumbles to dust, leaving behind Mamushi's Thornsoul Bulb, which Boruto claims in hopes of freeing Bug. Code's ambush at Bug's tree, combined with the bulb going unpreserved, rots Mamushi's core away, ending both Mamushi and Bug for good.