Sesshomaru is a fictional character in the anime and manga series InuYasha created by Rumiko Takahashi. He is the older half-brother of the series' protagonist, InuYasha. Sesshomaru's role in the series has varied from antagonist, to hero, and most often an anti-hero, depending on his current situation, but he is consistently shown as InuYasha's rival and the two have fought many times. Their rivalry runs deep, influenced primarily by Sesshomaru's hatred for half-breeds and his blaming InuYasha for the death of their father. He also hates InuYasha for possessing their father's legendary sword Tetsusaiga, which he believes is rightfully his.

Initially portrayed as a cold, stoic character with a hatred of humans, Sesshomaru undergoes a series of trials throughout the series that reshape his beliefs and his relationships with those around him. These trials include his care for an orphan named Rin, and his possession of his father's second sword Tenseiga, which can revive the dead.

Sesshomaru is the youkai son of the powerful Inu no Taishou and another, yet unnamed inuyōkai known only as Sesshomaru's Mother.Since Inu no Taishou is considered to be a daiyoukai , Sesshomaru is a daiyoukai himself. In both the manga and the anime, he appears stoic and hard to read. He rarely smiles, and when he does, it is usually not a good thing; Jaken once wanted Sesshomaru to beat him rather than to smile because it was Sesshomaru's smile that he feared more.Sesshomaru believes that struggle is the only way for survival, and throughout most of the series, he shows his contempt for InuYasha, his half brother.

Although Sesshomaru inherited his father's Tenseiga, which can bring 100 people back to life with a single swing, he originally coveted InuYasha's inheritance, the powerful Tetsusaiga. However, a barrier was cast around Tetsusaiga so that full youkai cannot wield it without burning their flesh. Even knowing that he cannot touch the sword,Sesshomaru still desires to take it from InuYasha. He fights with InuYasha in their father's grave and by chance, InuYasha transforms the blade and cuts off Sesshomaru's left arm.It is not until his fight with Magatsuhi that his left arm returns.By the time he regains his left arm, however, he is no longer interested in obtaining the Tetsusaiga.

He is followed by his retainer, an imp-like yōkai with a small beak named Jaken, and later by a human orphan named Rin, whom Sesshomaru brings back to life using Tenseiga, which he tells Jaken was merely a test of the sword. He is also followed by a two-headed dragon that Rin names Ah-Un. Also, Sesshomaru later saves Kohaku from Byakuya, resulting in Kohaku's decision to join his retinue as they leave Sesshomaru's mother's palace.It is also revealed that none of his companions can again be revived by the Tenseiga since they have all died before and were already revived by Tenseiga.