Hanyō

A  was a supernatural being who is part human and part demon. Hanyō are usually the child of a demon and a human, though humans can be transformed into hanyōs. Due to their dual nature, hanyō are often subject to prejudice from both human and yōkai societies because of the mutual hatred between both respective species.

Creation
There are two different ways to become a hanyō:
 * Natural Hanyō Birth: When a demon and a human procreate, this results in a hybrid offspring of a yōkai and a human. Apparently, in most cases, the father is a yōkai and the mother is a human.
 * Demonic Merging: Humans can turn themselves into hanyōs by merging their physical forms with that of a demon or demons. The most prominent example of such a half-demon is the spider hanyō Naraku.

It is more common for someone to be born a half-demon than to be unnaturally transformed into one.

Society
Half-demons are shunned both by humans and by yōkai. The miko Kanade built a magical barrier around Hōraijima, because she knew that the hanyō children would be only suffering from both humans and by yōkai.

Humans often believe that yōkai are dangerous and bloodthirsty monsters that kill humans without provocation. Sometimes the mere sight of a demon is enough to make humans flee in fear. And humans generally believe that hanyō are just as bad. For this reason, a half-demon is not welcome in a human village, and is often beaten and abused, as was the case with Shiori and Jinenji, who suffered numerous scars from the abuse. Sometimes a hanyō, however, also manages to be accepted by a human village, like Inuyasha and later Jinenji.

Yōkai despise hanyō, however. They also despise humans, and see in a half-demon an insult and weakening of their power. Yōkai even despise hanyō that are related to them, as Sesshōmaru did with Inuyasha, and Taigokumaru with Shiori. Sometimes they even want to kill half-demons for the very reason that they are half-demons. So Inuyasha was repeatedly attacked by low-tier yōkai, which resemble huge worms and beetles, whereas the Shitōshin have attacked Horai Island. Nevertheless, hanyō can make friends with benign yōkai, like Inuyasha and Shippō, or win the respect of evil yōkai, as was the case with Izumo and Orochidayū.

For this reason, the Shikon no Tama is interesting for many hanyō, because it can turn them into pure yōkai or pure humans. Some half-demons want to become demons, like Inuyasha at the beginning of the plot, and Naraku, because they get stronger and are respected by other yōkai. Others, like Izumo, want to be pure humans so that they can live in peace among other humans. But there are those who are content to be half-demons, like Jinenji, or Inuyasha at the end of the plot.

Physiology and Psychological Characteristics
Even at birth, hanyō show physical signs of their yōkai roots (e.g. unusual eye or hair colors, abnormal skin tones, and even physical abnormalities). For example, Inuyasha had silver hair and dog ears, a trademark of his inu-yōkai heritage, and the half-demon children of Hōrai Island had unusual hair colors and physical peculiarities (i.e. pointed ears or horns). While half-demons can be born with rather human-like features, there are some like Jinenji who are far more "monstrous" in appearance. In some, rare cases, there are also half-demons, which look purely human during the day, and become pure demon at night. Certain half-demons can even display unusual mannerisms and characteristics that pertain to their demonic heritage; for example, Inuyasha was known to perform dog-like actions (i.e. getting down on his hands and knees with his nose to the ground, using his foot to scratch his ear, playing fetch, shaking himself dry, and even growling).

The unnatural type of hanyō, formed by the merging of humans and demons, have almost completely human forms due to being originally human. However, their true form is primarily an amalgamation of demons fused together because they are essentially a colony of demons inhabiting a human body.

Powers and Abilities
The strength of hanyōs is remarkably varied, though they are normally stronger than ordinary mortals and more powerful half-demons can even stand on equal ground with full-fledged demons. Apparently the extent of a half-demon's power is a reflection of the power of their demonic parent. For example, the half-demon Inuyasha was exceptionally powerful, being the son of a powerful daiyōkai, and as an adult could dispatch most low-tier demonic foes with ease. It is noteworthy that hanyō as children are already very strong and resilient. So Dai could effortlessly break a branch that was as thick as a human arm, while Shiori fell from a great height and remained completely unharmed.
 * Enhanced Condition: A common ability amongst half-demons is inhuman strength, speed, endurance, resilience and/or recuperation. A half-demon can display any combination of these physical enhancements or the lack thereof. While Inuyasha had enhanced strength and could rapidly recover from injuries sustained on his body with no scaring, Jinenji, while having inhuman strength in proportion to his size, did not seem to be able to heal rapidly and retained multiple scars caused by ordinary iron or steel implements.
 * Unique Powers: Many hanyō also have special powers that are rare or unique, depending on what kind of yōkai their parent is. For instance, Inuyasha has sharp claws and can use his demonic power to solidify his blood for offensive attacks. Shiori can also create powerful barriers whereas Ai was implied to have some type of underwater adaption, given how she apparently swam the distance from the Hōrai Island to the mainland in a relatively short span of time.
 * Longevity: Half-demons can be supernaturally long-lived. Before being sealed to the Tree of Ages, Inuyasha was over a century old, but he maintained the vitality of a fifteen-year-old. The children of Horai Island have barely grown older in fifty years, and it is implied that they are much older.
 * Sharper senses: Hanyō and yōkai unite the senses of animal and human, analogous to the respective animal, but without the weaker senses of the animal. That's how Inuyasha can hear and smell as well as a dog, but his sense of sight is better than that of a dog, and it's the same as a human's.
 * Use of demonic weapons: When humans use demonic weapons, it does not take long for this weapon to dominate humans simply because they are not strong enough to withstand the demon that is part of that weapon (with the possible exception of Bankotsu). But hanyō can master such weapons effortlessly, even if particularly powerful weapons like Sō'unga can be too strong for them. It is also noteworthy that they can overcome barriers that should ward off yōkai. So Sara Asano could touch the sword Tessaiga without being warded off, even though she had evil intentions.

Weaknesses

 * Demonic Blood: In times of great fear or when their life is in danger, a hanyō can be overwhelmed by their demonic blood, becoming a pure-blooded demon. In this form, they benefit from increased demonic powers and the extent of this enhancement is dependent on the yōkai from which they are descended from. Inuyasha is the only hanyō that has ever experienced this transformation, and as a yōkai he is wild, cruel, and ruled by a violent blood lust. In addition, he can not distinguish friend and foe from each other, and attacks everything and everyone. It is even implied that these transformations are getting worse, the more they happen. This condition can apparently also be caused by magical items, such as the Mirror of Life of Kaguya, or Sō'unga.
 * Power Loss: According to Myōga, all half-demons are subject to certain times when they lose their supernatural powers as demons and are rendered no stronger than any ordinary human. For example, Inuyasha loses his demonic powers during the night of the new moon (which occurs once a month). Both Kōga and Inuyasha said that most half-demons hide in fear at the time. It was a great character development for Inuyasha to trust his friends and not to hide on the new moon night. Jinenji hides under a blanket at home while transformed, which occurs on a day while the sun is up, although he probably would not be a weakling because of his size and mass. Even spiritual places like Mount Hakurei seem to weaken a half-demon to such an extent that it turns into a human being for a short time. Half-demons formed by the amalgamation of demons and humans can apparently choose this period of weakness. Naraku was known to choose when he experienced a loss of power and would expel weaker portions of his physical form to grow in strength.
 * Spiritual Power: Hanyō are susceptible to the effects of spiritual power. This is inclusive of mystical objects such as sacred arrows, arrows of sealing, sutras, and the beads of subjugation.

By birth

 * Inuyasha
 * Izumo
 * Jinenji
 * Moroha
 * Setsuna
 * Shiori
 * Towa

Hōraijima children

 * Ai
 * Asagi
 * Dai
 * Moegi
 * Roku
 * Shion

Game exclusive

 * Gorai

By unnatural means

 * Naraku
 * Sara Asano
 * Tsubaki

Trivia

 * The term "Half-breed" is used as an offensive term for hanyō.
 * The term "hanyō" is composed of two different words. The first is "han", which means "half" in Japanese, and "yō" is the first syllable of the word "yōkai". Thus the literary translation is "half-yokai".
 * While most half demons in the series are born naturally from a demon and human parent, some are created artificially through demon magic.
 * Moroha is the only "hanyō" with less than half-blood. Having only a quarter of demon blood, she could technically be said to be a shihanyō (四半妖, "quarter demon").
 * In the movie, InuYasha: Fire on the Mystic Island, there is a secret haven known as Hōrai Island where yōkai and humans lived together in peace, raising many hanyō offspring who were accepted by all.
 * According to the miko Lady Kanade in InuYasha the Movie: Fire on the Mystic Island, the spiritual power a human possesses normally clashes with the demonic power of a demon, in half-demons this power merges and produces a unique synergy of these powers.