- Japanese Voice Actor: Katsuyuki Konishi
- English Voice Actor: Ray Chase
- Age: 23
- Manga Debut: Chapter 44
- Anime Debut: Season 1 Episode 21
- Race: Human
- Gender: Male
- Status: Alive
Tengen Uzui was born of shinobi. There were nine children in the family. All of them were harshly trained for them to be better shinobi. They were taught the importance of the clan and of killing innocent lives to save the clan. Three of his brothers died before they were ten because of the intense training.
With the remaining six siblings, his father had him fight his siblings. They were not aware of the identity of the people they were killing, as their faces were covered with masks. Tenzen, upon killing two of his brothers, discovered the trick.
When he was 15, he was married to three women. His clan practices polygamy and the sole reason for marriage is for them to bear more children. At the same age, 7 of his brothers were dead. Only he and his youngest brother were alive. The youngest brother had adopted the mindset of their father.
Tenzen left their village with his wives and started a new life. Tenzen would later teach his wives to value their lives above the mission. He was anguished about whether he should kill every member of the clan or not. Later he realized he could not kill his brother and father.
After leaving his village, Tenzen searched for Kagaya Ubuyashiki so he could join the Demon Slayer Corps. When he rose to the ranks of Hashira, Sanemi and Kanao were not Hashira yet. When he meets Tanjiro and Nezuko, he expresses disgust that Tanjiro is traveling with a demon.
While he got intrigued by why Tanjiro is traveling with Nezuko, he strongly disagrees that they should travel together. Tengen was the one who was given the assignment of infiltrating the Red Light District.
He is not supposed to work with Tanjiro, Inosuke, and Zenitsu. Still, when Tanjiro opposed using the unwilling demon slayers to infiltrate the District and volunteered himself, Tengen had no choice but to do his bidding. Tengen sent his three wives to infiltrate the district. The boys also gathered information in the district while Tengen would lie low.
Tengen sensed a danger when Zenitsu, who pretended to be a girl and worked at the Kyogoku House went missing. He investigated the disappearance himself, and after pressing the manager, he found that a certain Warabihime was causing the disappearances.
Tengen was able to save both Zenitsu and his wife Hinatsuru. When he fought Daki, he was able to decapitate her immediately and was even surprised that she was an Upper Moon.
Tengen was surprised by the presence of another demon Gyutaro. He poisoned Tengen and avoided getting decapitated. After Tengen defeated the demon siblings, he lost his left arm and eye. The poison of Gyutaro started spreading inside the body of Tengen.
Nezuko used her Blood Demon Art to burn the poison out of his system, and he was able to rejoice with his wives. Tengen informed Obanai that he was retiring as a demon slayer. Despite being a retired member of the Demon Slayer Corps, Tengen helped in the Hashira training.
He and his wives trained the members in the first level, which is basic stamina training. During the Infinity Castle Arc, Tengen, alongside Shinjuro Renguko, is on another side of the Ubuyashiki Estate when it was taken into the Infinity Castle. They stand guard outside the room of the surviving Ubuyashiki as they map out the castle to provide instruction to the demon slayers.
Tengen is a very tall man. He has a wide frame and is bulky. His white hair has uneven lengths, the longest reaching his shoulders. His thin maroon eyes seem to slant upwards. He is a good-looking man and uses his looks in missions where he needs persuasion.
As a demon slayer, he wears a turquoise sleeveless demon slayer uniform. He wraps a burgundy cloth around his calves, his tattsuke hakama pants tucked in, and white strapped zori sandals.
He wears golden rings around each of his arms and another for each of his wrists. The golden rings on his wrist appear to hold a pair of fingerless gloves secured on his middle finger. Tengen also wears a white head wrap.
Two chains of the gemstone can be seen hanging from his white headband. He wears red eye makeup around his left eye. The makeup consists of dots of different sizes that run inwards toward his eyes.
Tengen wants everything and everyone around him to be flashy. His eccentricity and flamboyant character can make him demanding of others. He treats the demon slayers harshly and insults them for not completing his training.
He hates the idea of being plain. He would always declare that he was the god of flashiness. He deeply cares for the people he loves, his three wives. He looks up to people like Kyojuro Renguko and his fellow Hashira.
Tengen is the second strongest Hashira in the current generation. His background as a shinobi makes him a skilled combatant with immense stamina, reflexes, and strength. He is an expert in stealth, as he learned this when he was a shinobi. He is capable of fighting two Upper Moons at the same time.
Although he was heavily injured and almost died, Tengen could match their skills. His tactical skills and sharp sense are a few of the skills he learned as a shinobi that were proven useful when he became a demon slayer. Using echolocation, he can easily detect underground battles. He also converts the enemy’s attacks into a musical score so he can easily read it.
Tengen uses dual-wielding Nichirin cleavers that he can wield using only one hand. Being one of the most powerful swordsmen in the entire generation, he easily adapted to Gyutaro’s mantis-style fighting. He also uses anti-demon bombs. He invented Sound Breathing. There are three known forms, and he masters them all.