Serpenters

The brothers are identical down to the detail: average frames, fair skin, indigo hair cut in a bowl, and yellow reptilian eyes ringed by dark purple markings. Large fangs crowd their mouths. Both dress plainly in red and white tunics over gray boots that appear to be snakeskin.

Trigger changes them. Patterns spread across their faces, their hair stands up in spikes, their jaws split wide enough to reach their ears, and their teeth sharpen, leaving them looking far closer to the animal they are named for.

There is no daylight between them temperamentally. Each is committed to seeing Flect Turn's design through, and their reason for signing on is self-preservation rather than belief: Humarise intends to wipe out Quirk users, and the twins have Quirks, so aligning with the organization was how they bought themselves an exemption.

Beyond that they are wildly unstable and permanently keyed up, delighted at the prospect of a fight and happy to kill whoever stands in front of them, cackling through all of it.

Humarise announces itself by detonating a Trigger Bomb in a populated city, killing thousands, and the World Heroes Association answers with simultaneous raids on every branch it can find. The sweep nets no bombs and no Flect Turn. The organization then seizes global communications to declare that twenty-five cities are wired to blow inside two hours, naming each one, a disclosure designed to pull heroes into a trap rather than warn anyone. Panic spreads across all twenty-five countries, and the WHA turns its heroes loose to calm the public and hunt the devices.

Scouts spot a chartered plane flown by Rody Soul closing on the headquarters with the Endeavor Agency's interns aboard, and Flect sends Leviathan and the Serpenters out to meet them. Katsuki Bakugo peels off to hold the twins while Izuku Midoriya and Shoto Todoroki push deeper toward the bombs.

Katsuki opens by asking why a Quirk user would serve an anti-Quirk cause. The answer, that Humarise has promised them a place in the world it intends to build, arrives alongside the reveal that there are two of them. He calls them cowards buying their own survival and starts firing. Sword Kill turns their arms into extendable bellow blades suited to both cutting and grappling, and the pair split in opposite directions, slip his blasts, and open him up. AP Machine-Gun fire gets sliced apart. They circle him, taunting, swinging themselves around the colonnade at the entrance whenever he closes, and they run him through more than once.

The chase was the point. Katsuki had been seeding grenades along one of the columns, and a shot from his Grenadier Bracer chains the charges and drops the whole structure onto them. They dig out by injecting Trigger, which multiplies their speed and strength and lets them field seven blades apiece, four sprouting from the upper back and one from the mouth. In that state they outclass him badly and come close to killing him.

He wins by letting them stab him. With their blades buried in his body, Katsuki seizes the limbs, refuses to release them, and uses Explosion to whip all three of them around until centrifugal force hurls the twins into the cavern wall. Both Grenadier Bracers fire; the brothers spit Sword Kills to shred the devices mid-flight, and the blast only wedges them harder against the stone. Pinned and out of options, they take Howitzer Impact head-on, which levels the entrance and buries them. With the bombs defused and Flect beaten elsewhere, the surviving Humarise ranks, the twins among them, are taken into custody. Supplementary material refers to the pair as the Twin Villains.