Do you believe in reincarnation? I believe that everyone who fought demons and died for a peaceful world was reborn into a happier life.
Yoshiteru shares a striking resemblance to Zenitsu Agatsuma, his great-grandfather, with black pelted hair and arrow shaped eyebrows. He is quite tall in comparison to his friends, as he is seen looming over the other students.
His school uniform consists of a light blue long sleeve shirt, accompanied by a white vest and black tie, as well as black slacks and brown shoes.
Similar to his great-grandfather, Yoshiteru is somewhat exaggerated in regards to his reactions. When he was reading the book which explained the battle against Muzan, he began crying over his ancestor's determination and willingness to risk their lives.
Yoshiteru has also expressed the flirtatious tendencies of his ancestor as he was seen gawking at female students, as well as being threatened by the reincarnation of Obanai Iguro for staring at his wife's chest, whom was the reincarnation of Mitsuri Kanroji.
Despite his flirtatious behavior, Yoshiteru is submissive to his sister and is somewhat afraid of her, saying that she's the opposite of quiet and polite. Upon hearing of her brother's actions, Yoshiteru immediately tries to defend himself in order to avoid his sister's scoldings.
Yoshiteru discovers his great grandfather's record of the battle against Muzan in a storage unit. Upon reading the book, he gets overwhelmed with emotion and is promptly berated by his sister for not studying. As they walk to school, Yoshiteru asks Toko if she believes in reincarnations and expresses his beliefs that everyone who fought the Demons, was reincarnated into a happy life.
As sister reads through the news, he snatches her phone and reads the article regarding Aoba Hashibira's discovery of the Blue Spider Lily. He becomes intrigued by her beauty and berates the public for criticizing her, but becomes furious when he discovers that Aoba was actually a man.
As they continue on their way to school, the siblings come across newborn twins which resemble Muichiro and Yuichiro as well as female students who resemble Shinobu and Kanae. Upon encountering Kanata Kamado, Yoshiteru begins to ominously curse him for flirting with his sister.
The group continues on their way to school, and passes a daycare along the way. Yoshiteru notices the kindergarten teacher, who looks like Gyomei, and mentions his large body. When Toko asks Kanata if he wants to visit a nearby restaurant, he declines mentioning that they were previously threatened with a knife by the owner,—who looks like Obanai—due to Yoshiteru's excessive stares at his wife's—who looks like Mitsuri—chest.
- Yoshiteru's first name contains the kanji "good" (善 yoshi?) and "illuminate" (照 teru?).
- He has gotten hit by a truck while protecting his sister. He managed to get saved without any large scars because of Toko applying first aid. He's a good guy inside, but he tends to be very unfair.
- He has saved his sister Toko from being run over by a truck once before, showing more parallels between Yoshiteru and Zenitsu, including the willingness to do good when it matters the most.
- (To Toko Agatsuma) "Do you believe in reincarnation? I believe that everyone who fought demons and died for a peaceful world was reborn into a happier life."