One of the greatest brother rivalries in anime is between the full-fledged demon Sesshomaru and the half-demon Inuyasha. In Inuyasha, Sesshomaru hates his half-human brother and has a bloodthirsty desire to obtain his father’s Tessaiga, a sword that can slay one hundred demons. However, his selfishness and power-hungry nature prevent him from inheriting the sword. As a result, Sesshomaru goes on a journey of self-discovery, learning about compassion and selflessness through his encounters with Rin and Kagura. His prejudice softens to the point that, in Yashahime: Princess Half-Demon, he has two half-human daughters.
Inuyasha vs. Sesshomaru: Sword Inheritance Battle
At first, Sesshomaru detests all humans and half-demons. Sesshomaru despises his half-brother Inuyasha because he cannot accept that his father’s blood runs in Inuyasha’s veins. He constantly taunts and insults Inuyasha for his half-breed pedigree. His hatred grew when Inuyasha became the master of the Tessaiga. When they visit their father’s tomb, Sesshomaru is unable to pull the sword out, implying he isn't destined to inherit it. When Inuyasha swears to protect Kagome from Sesshomaru, the Tessaiga pulses and transforms into a large fang, claiming Inuyasha as its owner. Inuyasha concludes their father must have intended to give the sword to him since his father's tomb was in his eye.
The Tessaiga is a sword of protection. According to Myoga, it was created to protect Inuyasha’s mother, Izayoi, a mere mortal. Inuyasha’s feelings for Kagome allowed him to wield the Tessaiga. In contrast, Sesshomaru lacks empathy towards humans and is unworthy. Even though the Tessaiga doesn’t belong to him, Sesshomaru keeps trying to obtain it. He attempts to steal the Tessaiga by joining forces with Naraku and even creating a new sword called the Tokijin to match the power of the Tessaiga. However, he fails to achieve his goal. Eventually, Sesshomaru begins to question why his father didn’t give him the sword in the first place.
Rin & Kagura: A Change of Heart
Sesshomaru meets Rin in Episode 35, “The True Owner of the Great Sword!” After losing a battle against Inuyasha, Sesshomaru retreats to the forest. Rin, an orphaned girl, sees Sesshomaru badly injured and decides to give him food and water. Sesshomaru refuses the food, remaining cold and distant from her until he asks about the bruises on her face, which she takes as a sign he's showing interest in her. One day, Rin gets mauled to death by wolf demons, and Sesshomaru uses his Tenseiga to revive Rin. It may appear that Sesshomaru is repaying a debt towards Rin, but she sees this as an act of kindness and decides to follow him on his journey.
In Episode 162, “Forever with Lord Sesshomaru,” Rin’s loyalty towards Sesshomaru is demonstrated when she's kidnapped by a demon named Ongokuki and saved by a monk named Ungai. Ungai plans to take her back to his village, but she insists on staying with Sesshomaru. It surprises Ungai to see a human girl not fearful of a demon. Humans have treated Rin poorly throughout her life, but Sesshomaru has treated her well, like an older brother figure towards her. Whenever Rin is in danger, he always comes to her rescue, and such devotion has shaped him into being more caring towards humans.
His caring nature is also shown when he comes to save Kagura, one of Naraku’s reincarnations. In Episode 169, “Kagura’s Wind,” Sesshomaru plans to save Kagura with the Tenseiga. Although he isn’t able to save her, his very act of trying to rescue her is enough to show that he values life, whether demon or human. Before, he was selfish and did not care for others. His willingness to save Rin and Kagura’s lives indicates that Sesshomaru is changing his perspective on others, which also contributes to his growing tolerance of Inuyasha.
Sesshomaru may remain aloof towards Inuyasha, but there are instances where Sesshomaru is willing to help Inuyasha in his fight against Naraku. For example, after Kagura’s death, the Tenseiga sees Sesshomaru as a worthy master and calls forth Tōtōsai to teach the "Meido Zangetsuha" to Sesshomaru. Later on, Sesshomaru challenges Inuyasha to see if he's worthy of wielding the"Meido Zangetsuha." By teaching the "Meido Zangetsuha" to Inuyasha, Sesshomaru finally matured, marking the end of his obsession over their father’s legacy. This sign of maturity leads Sesshomaru to produce his sword, the Bakusaiga, from his body in Episode 184, “Magatsuhi’s Evil Will.” Tōtōsai explains that the Bakusaiga was always within Sesshomaru, but it would only reveal itself once Sesshomaru becomes a great demon without the support of his father’s legacy.
Yashahime: Two Daughters
After defeating Naraku, Sesshomaru decides to let Rin reside at Kaede’s village so that she can adapt to human life. In Yashahime: Princess Half-Demon, Sesshomaru has half-demon twin daughters, Setsuna and Towa. The name of their mother has yet to be revealed, but many fans suspect the mother to be Rin. One hint supporting this theory is in Episode 3 of Yashahime, “The Dream Butterfly,” where Sesshomaru takes his twin daughters away from Kaede’s village, where Rin resided at the time.
Although Sesshomaru is constantly mentioned to be Setsuna and Towa’s father, the twins do not acknowledge him as one since he hasn’t been around them when they were children, similar to Moroha’s parents. Although Sesshomaru is indifferent towards his children, Sesshomaru still shows concern over Rin, who is imprisoned in the Sacred Tree in Episode 4 of Yashahime, “The Gateway to the Past.” Although there have only been glimpses of Sesshomaru so far in the new spin-off series, viewers can safely assume that he will have a bigger role later on as the story progresses. For now, his presence the proof of how dramatically his views on humans have changed.