“Wait,” Ikoma protested, having given up trying to keep Kibito and Kajika from fussing with his sling. Even if the bushi was now adding a padded glove to just peep out at the end, which was absolutely ridiculous. Unless, of course, Mumei’s smirking explanation actually was meant to explain. “What do you mean, it’ll grow back?”
“We are half-Kabane.” Mumei gave him a frown of this should be obvious. “With enough blood, we regenerate.”
“Which makes me think twice about your habit of collecting parts.” Sukari lingered on the locomotive stairs; from that upward tilt of blond brows, all too glad to not be the victim of Kajika’s fussing. “Not to mention all those Kabane our bushi beheaded and tossed out. Are they still wandering around out there like headless ghosts?”
“Parts don’t grow whole new Kabane,” Ikoma muttered, flexing his stump against the padding. Maybe it was a little longer than yesterday… but that could be wishful thinking. “I did my research before I ever started picking up pieces of blood vessels. Once the heart’s destroyed, the Kabane is dead.”
“But beheaded Kabane aren’t dead.” Mumei tapped a finger against her lips, dragging up yet more obvious facts that no one who wasn’t a Hunter would have ever heard of. “They can’t see, and they can’t bite. But if they can tear someone open and pour the blood down the stump, they’re still dangerous.”
Ikoma froze. Traded a glance with Kibito, who looked almost as unsettled at the thought of Kurusu’s beheaded Kabane wandering the tracks behind them.
“Good thing you reinforced a sword for him,” Kibito observed. “We’ll all feel better if he stabs them through the heart.”
A/N: I admit part of this is headcanon. But… it’s headcanon based on what Mumei says about Kabaneri healing in ep 3, and we see in the last 2 eps.
Seriously, it’s clear in ep 10 exactly where Ikoma got shot in the arm – well above the elbow. Ep 11, the remaining stump is visibly longer, and by the end of 12 he can actually put it in a sling. Which kind of requires having an elbow.
And yes, canon, beheading a Kabane doesn’t kill them. Slows them down, definitely. But they’re not dead. You have to pierce the heart for that.