Inuyasha is the central character of his namesake series, a half-demon, or hanyō, born from the union of a powerful dog demon lord and a human princess named Izayoi. This dual heritage is the defining fact of his existence, shaping his identity and his place in the world from the very beginning. Orphaned at a young age, he was rejected by humans who feared his demon side and despised by full demons who viewed his human blood as a stain on their kind. This lifelong ostracization left him with a deep-seated feeling of isolation, making it incredibly difficult for him to trust anyone. His primary motivation becomes a desperate desire for acceptance and power, which he believes he can achieve by using the Shikon Jewel, a powerful magical artifact, to transform himself into a full-fledged demon.

Before the main story begins, Inuyasha meets the priestess Kikyo, the guardian of the Shikon Jewel. Despite their initial animosity, they fall in love. For the first time, he finds someone who accepts him, and he is willing to abandon his dream of becoming a demon to live as a human with her. However, the evil demon Naraku orchestrates a tragic betrayal, tricking them into believing the other has turned against them. In the ensuing conflict, Kikyo seals the heartbroken Inuyasha to a sacred tree with a magical arrow, where he remains in an enchanted sleep for fifty years.

His story truly begins when a modern-day schoolgirl named Kagome Higurashi releases him from the seal. She is the reincarnation of Kikyo and unknowingly possesses the Shikon Jewel, which is soon shattered into countless shards that scatter across feudal Japan. Inuyasha's initial role in the story is to partner with Kagome to recover the jewel shards, driven by his own selfish desire to use the completed jewel for himself. However, this simple partnership quickly evolves into a deeper quest to defeat Naraku, who is also hunting for the shards, and to avenge the suffering he has caused.

Inuyasha's personality is as fiery and direct as his appearance. He is famously short-tempered, proud, and impulsive, often charging into battle without a plan and speaking his mind with little regard for diplomacy. He frequently quarrels with his companions, especially Kagome, whose "sit" command, enforced by the Beads of Subjugation around his neck, can instantly force him to the ground. Despite his brash exterior, he possesses a fierce loyalty and a hidden but deep well of compassion. He is offended by any implication that he is weak because of his human heritage and hates being called a dog. A complicated relationship defines his past with Kikyo, whom he still feels a powerful sense of duty and lingering affection for. In the present, his bond with Kagome becomes the emotional core of his character. While he struggles to articulate his feelings, he grows to deeply trust and love her, often risking his life without hesitation to protect her.

Throughout the quest, Inuyasha forms a surrogate family of allies. He is joined by the lecherous monk Miroku, the demon slayer Sango, and the young fox demon Shippo, all of whom have their own grudges against Naraku. He bickers constantly with Shippo but acts as an older brother figure. He respects Miroku and Sango as formidable warriors. His relationship with his older brother, Sesshomaru, is one of intense rivalry and hatred, stemming from Sesshomaru's contempt for Inuyasha's human blood and his desire to claim their father's powerful sword, Tessaiga, which Inuyasha wields. This sword is a fang of their father transformed, and its power is central to Inuyasha's role as a fighter. As a half-demon, Inuyasha has a significant weakness: on the night of the new moon, he transforms into a fully human, losing all his demonic powers and abilities.

Inuyasha's development is the heart of the series. He begins as a cynical loner who trusts no one and cares only about gaining power for himself. Through his experiences with Kagome and his companions, he learns to trust, to rely on others, and to fight not for personal gain, but to protect the people he cares about. His journey involves coming to terms with his identity, no longer seeing his human half as a weakness but as an integral part of who he is. Ultimately, he finds the acceptance he always craved, not by changing what he is, but by finding a place where he is valued for himself.

In combat, Inuyasha relies on a combination of his natural half-demon abilities and his inherited sword. His demonic traits grant him superhuman strength, speed, agility, and a remarkable healing factor that allows him to recover from severe wounds. He wields his own claws in a devastating technique called Sankon Tessou, which can tear through most enemies. His primary weapon, however, is the Tessaiga, a legendary sword that transforms from a rusty blade into a fang-like weapon capable of slaying a hundred demons in a single swing. The Tessaiga has a protective barrier that shields him from demonic attacks and possesses several powerful techniques. His signature move is the Wind Scar, a powerful energy slash created by striking the intersection of two opposing demonic auras. He later masters the Backlash Wave, an even more powerful attack that returns an enemy's energy against them. The sword can also absorb the abilities of defeated demons, giving Inuyasha new ways to break through barriers or launch diamond shrapnel at his foes. A dangerous aspect of his demonic heritage is that when his life is in extreme peril, his demon blood can take over, transforming him into a feral, unstoppable beast with immense power but no rational thought.