“Wow, you’re annoying. You know I have no brother.”
- Japanese Voice Actor: Tomokazu Seki
- English Voice Actor: Kaiji Tang
- Age: 21
- Manga Debut: Chapter 45
- Anime Debut: Season 1 Episode 22
- Race: Human
- Gender: Male
- Status: Alive
Sanemi was born as the eldest son of 7 children. His father is abusive, and his mother protects them against his father. All the villagers hate their father. Their father was stabbed and killed by someone who has a grudge against him.
They were then left in the care of their mother. One night, their mother was late in coming back, so Sanemi left his siblings in the care of his younger brother Genya so he could look for their mother. When Sanemi found their mother, she had already become a demon.
He could not stop her from returning home. She killed five of his siblings. When she was about to attack Genya, Sanemi tackled her from the window to the street while holding a knife. While they were fighting, she gave him two large scars across his face.
His marechi blood, which disorients demons and makes them act intoxicated, gave him an opening, and he cut her down. When Genya went to the streets to look for a doctor to attend to their other siblings, he saw Sanemi holding a knife with their dead mother at his foot.
Genya, not knowing that the demon that attacked them was their mother, accused Sanemi of murder. Sanemi abandoned Genya and hunted demons. He does not know what Demon Slayer Corps or Nichirin Swords are. He would hunt down demons and tie them down until sunrise.
One time he met Masachika Kumeno, who helped him become a member of the Corps. When Sanemi became a member of the Corps officially, he teamed up with Masachika, and they fought Lower Moon 1 and defeated it. Masachika died, and Sanemi was the only one who got promoted to Hashira. When he came face to face with Kagaya, he started criticizing him.
To his surprise, Kagaya accepted the criticism and told him about Masachika and his will. Sanemi cried after hearing that Kagaya knew every member of the Corps who died during his time as a leader. When Sanemi was promoted, Gyomei, Kanae, Tenzen, and Giyu were already Hashira.
He was scolded by Gyomei, Kanae, and Tenzen about his attitude while Giyu stood at a distance. As a member of the Corps and a Hashira, Sanemi abides by the rules and condones all kinds of demons.
When Tanjiro and Nezuko arrived at headquarters, Sanemi tempted Nezuko with his blood when Tanjiro told him that Nezuko would never hurt another human. When Kagaya finally reprimanded them that the issue was over, it was only then that Sanemi stopped. When Kyojuro Renguko died, Sanemi vowed to exterminate all demons.
During the Hashira training, Sanemi told Tanjiro upfront that he had not accepted him. He got impressed by his guts when he told him that he had not accepted him either because he was the one who stabbed Nezuko.
Sanemi had been avoiding Genya, his little brother since he joined the Corps. Genya told him that he had become a demon slayer so he could find him. Sanemi told him he no longer had a brother. Sanemi shows utter disgust when he meets Genya.
Tanjiro, however, told Genya that Sanemi never hated him and he still cared for him. Sanemi got angrier with Genya when he said he had no Breathing style as he could not master it, but he could eat the flesh of demons and use their ability.
Sanemi survived his battle with Kokushibo, the Upper Moon 1, in the Infinity Castle Arc. He, alongside Gyomei, Muichiro, and Genya, had fought Kokushibo. Genya and Muichiro did not survive the battle. Genya told his brother before he died that he needed to survive as his brother was so kind.
After the battle in the Infinity Castle and Muzan was still alive, the battle ensued. During the fight with Muzan, many members of the Demon Slayer Corps lost their lives. Sanemi had survived the battle. When he met Nezuko again, he patted her head and told her she reminded him of his late brother Genya.
He is a tall man with spiky white hair and large pale purple eyes. He has scars all over his face and body. He unbuttons his green-tinted demon slayer uniform, exposing his chest and abs. He wears a white long-sleeve shirt over it with a kanji kill written on its back.
He wears white buckles around his shins. He also wears tabi socks and white zori with green straps. He lost his right index and middle finger during his fight with Kokushibo.
An abrasive, hot-blooded, and stubborn man is what Sanemi is. He only shows reverence to Kagaya Ubuyashiki. After losing his parents and siblings, he became cold and indifferent. Despite his cold behavior, Sanemi cared for his brother deeply.
He does not want him to be part of the Corps for him to save Genya. His hatred toward demons had been extreme, as he had lost the people he loved because of them.
Sanemi is one of the most skilled swordsmen and combatants in the entire organization. His stamina, endurance, and strength are immense. During the Hashira training, he could hold off a lot of demon slayers when they had to face his training which was having combat with him until the demon slayers could no longer fight him.
He brawled against Tanjiro, and other demon slayers tried to break the fight but failed to do so. His swordsmanship was commended by Kokushibo when he fought against him during the Infinity Castle Arc.
Sanemi has marechi blood, which has helped him tremendously when fighting demons with any weapon he could take hold of. He would use his blood to intoxicate the demons, and he would then kill them. His sense of survival is one of a kind.
This developed his versatility in using any weapon when fighting. Although, as a member of the Corps, his weapon of choice is a standard Nichirin katana.