Strongarm

Kendo Rappa carries this emitter Quirk, listed at close range and introduced in Chapter 142 before reaching the anime in Episode 72. The English dub renames it Power Shoulder, and the Japanese title translates roughly to "strong throwing arm."

The name points at the anatomy that matters. Nothing about the ability enhances the fists themselves; everything traces back to how fast the shoulders can turn.

The Quirk permits shoulder rotation at extraordinary speed and force, and that motion is what feeds the punches. What emerges is a strike that combines velocity and weight beyond what an unaugmented arm could deliver.

In practice Kendo throws them in floods rather than singly, chaining blows that are both blindingly quick and immensely heavy. The cumulative shock is the real weapon: he wore down Fat Gum, a Pro Hero whose Fat Absorption is built specifically to swallow impact, purely through the concussion behind his fists.

Kendo Rappa is the sole holder, and the drawbacks are as pronounced as the output. Keeping his shoulders spinning at superhuman rates wears his muscles out if he presses too long, a cost he tends to ignore, and the power can only be sustained for a handful of seconds at a stretch.

Raw force also has a hard limit. For all its violence, the barrage could not break through the Barrier Quirk fielded by Hekiji Tengai, a defense that simply refuses to yield to volume.