Quirk Works
Trying to connect my science studies to anime because I may or may not be neurodivergent and am without a doubt BHNA simping trash.
Our favorite hard boi has willful control his stratum basale’s production of keratinocytes! Dude can instantaneously create an insane amount of Keratin.
Keratin is a protein found in the epidermis and has a variety of functions. It creates the tough exterior to our skin (hardening) and prevents the entrance of microorganisms (this dude never gets sick or ringworm). I’m even surprised that he got that precious eye scar with that type of skin control. For all intents and purposes he should be able to heal it but probably doesn’t because it looks manly. I’m still trying to work out what about him deactivating his quirk makes his skin go back to normal rather than sloughing off like a reptile. They tend to shed their epidermis all in one go (think snakes). However this dude just re-sucks in that 15-20 layers of dead skin with anime magic. Or maybe he does molt we don’t know about it?!?
Mind you our meat sack, as is, weighs about 20lbs (sans organs) so that would explain his workout mentality. He needs the extra muscle to be able to maneuver when those extra layers of skin on. It would also explain why he is so hard to knock back.
I started wondering what this may do to his somatosensation. His Merkel’s discs and Meissner’s corpuscles are probably useless during hardening. They’re sensitive to light touch and there is no way light touch is getting through those layers skin layers. However that may put him at a disadvantage to sensing when his shield is pierced with finer tools like thin blades or crazy thick needles (I’m thinking Toga sized) which would also contribute to slow reaction speed. Maybe he could learn to densely pack the Keratin for more streamlined movement that wouldn’t change his mass.
Sitting between the epidermis and the dermis (which is a layer down) we have arrector pili muscles which control our hair standing on end. It’s more of a vestigial or useless trait in humans. Our hair stands up when we’re uncomfortable or cold but we don’t have enough for it to actually make a difference. However Kiri may be able to use those muscles to his advantage. Maybe he could create fine spines like a porcupine? Otherwise I assume that hardening completely covers/blocks follicles. This guy could probably make a full beard disappear in seconds with the use of hardening.
Please suggest other characters or science for me to indulge in or correct me in the notes!