Being a half-demon has its perks, particularly in a world as dangerous as Inuyasha's, but it can come with its fair share of drawbacks. The son of a full-blooded demon and a mortal woman, Inuyasha initially sets off at the start of the show to eradicate his mortal blood and become a pure demon, propelled no doubt by his inability to fit into either side of the human and demon worlds. Despite his protested Hanyo status, Inuyasha has a lot to thank his father’s demonic blood for, though it has made for some bizarre physical features.
Inuyasha Has Accelerated Healing
You have Inuyasha’s demon half to thank for his ability to move from fight to fight while sustaining heavy wounds. Provided he has enough rest and the new moon doesn’t come into conflict, Inuyasha can heal injuries that would undoubtedly be fatal had they been inflicted on pretty much anyone else. Scrapes and cuts can be mended without any trace of scarring, while teeth can be regrown in as little as a day. These abilities have gotten him out of any number of tough situations, particularly when his Tessaiga was broken and required one of his fangs to be mended. While the extent of his healing capabilities has not been fully tested, it’s implied that these abilities have limits-- he’s still vulnerable to disease, and something as complex as a limb isn’t likely to be regenerated.
Inuyasha Can Harden His Blood
Another ability that helps him on the battlefield, Inuyasha is shown to be capable of manipulating and hardening his own blood. Among other things, this helps him to be more durable in battle, allowing him to withstand punishing blows and still continue fighting with only minimal scrapes. It additionally functions as an emergency weapon, blood drawn from a wound can be hardened into sharp projectiles which are then thrown at his enemy.
Affectionately called his Blades of Blood, the projectiles seem to mimic his claws, which are his preferred method of unarmed combat. These work best as a sucker blow, particularly when a wound has been inflicted by an enemy as his opponents tend to believe him to be weakened and consequently lower their guards. When an open wound isn’t available to him, however, he’s just as capable of using the stealth move, cutting his palm with his sharp nails as though clenching a fist before flinging the projectiles.
Inuyasha’s Demon Form Is Temporary
In a bizarre reverse-werewolf situation, this half-dog half-man has learned to fear the new moon rather than the full one. A product of his human mother’s mortal blood, Inuyasha loses all demonic abilities once every moon cycle and must barricade himself from the outside world as a weakened mortal man. Since this leaves him vulnerable to attacks from both demonic and human enemies, the date of his transformation is intended to be kept secret, though all hope of protecting the secret went out the door when the notoriously talkative Shippo learned about it.
Most of the changes seem to be only physical, with his hair and eye color changing, dog ears disappearing and his fangs and claws shortening to a humanoid state. However, he also seems to sustain some internal shifts as well. Inuyasha’s heightened senses of hearing and smell are lost, and his emotions seem to grow stronger. When in his human state, Inuyasha is shown to be more affectionate towards Kagome, while dwelling uneasily upon the emotionally stunted monster he may become should he complete the transformation into a full-fledged demon.
Inuyasha’s Senses Are Too Strong
On paper, possessing a dog’s heightened senses may seem like a handy benefit, but in practice, it’s often less than ideal. Sensory overload seems to be consistently detrimental to Inuyasha, with smells that register only as strong to the human nose capable of knocking him out. He can easily get confused when an overwhelmingly strong scent placed near him, which can be detrimentally distracting when he's attempting to use his sense of smell to track a target. His sense of taste is heightened as well, making him comedically weak to spicy foods due to taste buds far more sensitive than that of a human’s.
While his strong senses are doubtlessly double-edged, they come with enough benefits to outweigh the negatives. Inuyasha’s sense of hearing is remarkably acute, capable of hearing the whispers of those standing a good distance away from him. His nose can track the smell of blood and the presence of people from miles away, which functioned to his benefit while tracking Naraku. This also means that he can detect whether or not he and his comrades are being followed by fellow demons, giving them precious moments to prepare to defend themselves before they are attacked.
Inuyasha’s Nose Is Always Wet
Inuyasha’s enhanced senses, speed and general physical capabilities are granted to him by his doglike features. Though features such as the white dog ears perched at the top of his head are most noticeable, others tend to fly under the radar. For instance, Inuyasha’s nose is said to always be damp, much like a typical dog’s is, despite appearing relatively normal-looking design-wise. This feature is typically only teased by Kagome, though it can cause some concern as it only dries up when he’s suffering an illness. His fingernails additionally function as claws, despite only seeming to be slightly sharpened past the length of typical human nails, and are capable of cutting through demon hide and metal with equal efficiency. His canine teeth are elongated past typical human lengths and grow to become fangs, which can be regenerated within the span of a day.
