“Unless I die and get a different body in which this filthy blood does not flow, I have no right to be with you.”
- Japanese Voice Actor: Kenichi Suzumura
- English Voice Actor: Erik Scott Kimerer
- Age: 21
- Manga Debut: Chapter 4
- Anime Debut: Season 1 Episode 22
- Race: Human
- Gender: Male
- Status: Deceased
Obanai was the only boy born into a family of female thieves. His family has extraordinary wealth because they live off the riches of people that the demon they worship would kill. Babies born in his family would also be offered to the demon.
Obanai was the first boy born in the family for the last 370 years. They spoiled him too much and put him in a wooden cage. His family would bring him all the best food available, and he would get sick. His room has poor ventilation, so it has a pungent smell from all the food brought into the cage.
The serpent demon, who took the form of a snake-like woman with a lower body and face, took a liking to him because of the different colors of his irises. The demon would slither around his cage during the night. This would frighten him, and he would not be able to sleep.
When he was 12, he could go outside his wooden cage. He was brought to an expensive shrine where he was face-to-face with the demon. He immediately realized the same demon would slither outside his cage at night.
When the demon saw him, he was too small to be eaten, so he decided to wait until he had grown. The demon then had Obanai’s cheeks cut. It was cut from the corner of his lips to his ears so he would have the same mouth as the snake.
The demon had every blood dropped from Obanai’s cut in a cup. The demon then drank the blood like it was sake.
When he realized his fate, he planned an escape. Using a stolen hairpin, he would scratch the wall of his cage. Obanai made friends with one serpent, and he called it Kaburamaru. Kaburamaru is the only being that Obanai can trust.
The demon almost caught up with him, but he met the Flame Hashira, Shinjuro, who saved him from the demon. When Obanai escaped, the demon killed and ate all 50 of his relatives. The sole survivor, his cousin, blamed him for what happened to their family.
His guilt from losing his family for him to live made him join the Demon Slayer Corps. He directed all his anger toward killing demons. When Tanjiro and Obanai first met, Obanai had to pin down the former to remind him that he needed to bow down to his superior. When Kyojuro died, Obanai was in disbelief and stared at a distance.
At the end of the Entertainment District Art, Obanai went on to meet with Tenzen to discuss the slot that Kyojuro had left. He also discussed that lower-ranking demon slayers are losing. Tenzen told him that Tanjiro had been improving greatly, much to his surprise.
Before the Hashira training, Obanai and Giyu argued over the demon slayer mark. After Muichiro and Mitsuri gained the mark and Amane told the other Hashira that those who gained the mark were closer to defeating Muzan, there was a suggestion from the Hashira that everyone should awaken their mark.
Giyu disagreed, as he believed that gaining the mark was not that simple. The argument among the Hashira continued to heat up, and Gyomei had to slam the table to keep them quiet. He then proposed a training where each Hashira would train the lower-ranked members in a specific skill. For Obanai, he needs to train them in swordsmanship.
During the training, Tanjiro took four days to complete the training of Obanai. This includes slashing his sword while going through traps. It turns out that Obanai used people as part of his trap. These people were the ones who got on the bad side of Obanai.
When Tanjiro finally completed the training, he was told to get out and stop talking to Mitsuri. After the Hashira training, they fought Muzan, who attacked the Ubuyashiki Estate. Kagaya blew up the estate and heavily wounded Muzan.
When the Infinity Castle blew up, they thought Muzan was dead, but when they saw him alive, they continued the fight. Obanai seeing that Mitsuri was heavily wounded and was out of commission, decided to bring her somewhere safe.
Obanai then returned to battle. Sadly, Obanai was one of the Hashira and members of the Demon Slayer Corps who sacrificed their lives to save humanity.
Obanai is a short young man with a pale complexion but a muscular build. His hair is black and has different lengths. He has unusual eyes; his irises have different colors. His right eye is yellow, and his right is turquoise. His mouth is hidden under the bandage.
He wears a blue version of the Demon Slayer Corps uniform. He wears a black and white striped haori. He wrapped his legs with bandages to make them look like kyahan. He also wears a white zori with a blue strap. Kaburamaru was always with Obanai, wrapped around his shoulders.
He is a hot-headed young man. He is harsh and strict and hates the people who do not abide by the rules of the Demon Slayer Corps. He does not care about anybody else in the Corps aside from Kagaya and Mitsuri.
He would even shower Mitsuri with gifts, eat with her, and talk to her about cats. He hates himself, blames himself, and always feels guilty for his family being killed by demons. He believes they died because of the freedom he sought.
Obanai has a fear of women because he grew up around them. Mitsuri was the only woman he allowed to touch him. He never believed he deserved Mitsuri. He believes he will only deserve her if he dies, gets cleansed, and is reincarnated.
He has a strong sense of determination; this was shown when he fought Muzan. Despite being blind, he continued to fight.
As one of the demon slayers and was chosen by Gyomei to train those who have lower rank in swordsmanship, it is a testament to how good he is with the sword. It was revealed that he was blind in his right eye. Becoming a Hashira with only one functioning eye and defeating countless demons only shows how great of a combatant you are.
His disability of being able to see with only one eye made him utilize his pet snake Kaburamaru. Kaburamaru can predict the opponent’s next movement, which has always been right.
Obanai was able to awaken his Demon Slayer Mark while fighting with Muzan. With his mark and bright Nichirin Sword, he could easily maneuver and defeat the lower-rank demons. He also has immense reflexes, stamina, and endurance.
A twisted Nichirin katana is his weapon of choice. This is useful when he uses his Snake Breathing style, which he was able to master all five.