First Manga Appearance: Chapter 162
Name Meaning: Tamaru=to collect; to gather; to endure, Yoshi=good
Gangs: Oni-baku Gumi, Yagyo Atsuki
Previous Schools: Tsujido High School
Weapons: Type fourteen 9mm Nambu pistol
Transportation: Honda X-JR 1200
Notable Features: Timid looking, small stature, attached to his granddad
A small, quiet boy growing up, he is often the target for bullies. He lives with his mother & granddad. In junior high, he is known for his attachment with his granddad. He 1st appears at Tsujido being bullied in the locker room for money & gets saved by Eikichi. Impressed by Eikichi’s ability to scare off the bullies with a few words, he aspires to be stronger. He changes his hairstyle & look to match Eikichi & joins the Oni-baku Gumi. Eikichi gives his pants to Tamaru, which is considered a special honor, much to the K. T. Butai’s disappointment as they have also been hoping for the pants.
His newfound friendship with the Oni-baku Gumi causes the bullies to seek revenge & murder his dog Shiro. Tamaru reverts back to his old look & begs Eikichi for help. However, Eikichi tells him to take care of it himself if he is a man & takes his pants back. With no other options, Tamaru resorts to using a blade to confront the bullies but is stopped by Eikichi, who proceeds to take down the bullies himself. Eikichi then tells Tamaru to never do anything stupid again & states that Tamaru will never be tough.
That night, Tamaru arrives home to find his granddad has died in his sleep, leaving behind a suitcase with a 14 9mm Nambu pistol & his last words were for Tamaru to be strong. Determined to become stronger, Tamaru uses the gun to form the Yagyo Atsuki demon gang by walking around Shonan with his gun & creating rumours about his power. He orders them to start attacking students, starting with Fujiryo High and Enoshima High, leaving the carvings “oni” on his victim’s bodies.
At school, he maintains his friendship with the Oni-baku Gumi & tells Eikichi that he will protect them from Yagyo Atsuki. Later, Tamaru targets Atsushi Homna after he dismisses Tamaru as an amateur & denies his help to “fight” Yagyo Atsuki. He announces his assault on Tsujido by painting his “oni” symbol outside the school classrooms. In front of Eikichi, he declares that he will take out Atsuki Yagyo on his own to prove his toughness.
He orders his men to take out Atsushi before Atsushi gets the chance to reveal his secret to the Oni-baku Gumi. The Oni-baku Gumi has noticed Tamaru’s change in behaviour since the death of his granddad but fears that their friend’s actions may lead him to be caught by Yagyo Atsuki. Tamaru attacks Nagisa in her bus but leaves her unharmed as a warning to Ryuji. At Tsujido, Nakajo & Eikichi confront each other, each believing that the other is Yagyo Atsuki. Tamaru uses the opportunity to lure Tsukai into the school gym & attacks him, leaving the Oni-baku Gumi & Nakajo more confused than ever.
Seeing himself replace Ryuji in the Oni-baku duo, Tamaru targets him next & uses Kashiya, an Enoshima High transfer student, to lure Ryuji into an ambush. However, Ryuji is able to hold his ground & he arrives at the scene with the Oni-baku Gumi. Determined to prove his strength to Eikichi, he starts beating the Yagyo Atsuki demons brutally until he is stopped by Eikichi. Eikichi tells him that he has gone too far & Ryuji dismisses him from the group.
Angry at the Oni-baku Gumi, he issues his men orders to kill Ryuji. He stages a call to Ryuji begging for help, saying that he is caught by Yagyo Atsuki. Ryuji is ambushed at the abandoned warehouse & just as Tamaru is about to attack Ryuji from behind, they are interrupted by Eikichi, who has arrived with a bandaged Atsushi. Atsushi reveals his attacker & the true identity of Yagyo Atsuki to be Tamaru. Tamaru offer Eikichi to team up with him. Eikichi declines & he states that he will force Eikichi to serve him before riding off with his demons.
Declaring war on the Oni-baku Gumi, Tamaru orders his demons to ride through Shonan, attacking everyone in sight to lure Eikichi out. He is confronted by Eikichi, who states that he knows the contents of the bag Tamaru’s granddad left him. He pulls out his gun & points at Eikichi, taunting him that he is no match for the gun. Eikichi warns him about the backfire risks the gun has. His demons start to back up behind Eikichi & Tamaru fires the gun. The gun backfires & he injures his fingers. As he is taken to hospital, Eikichi calls him a fool for relying on weapons.
Two weeks after the incident, he returns Eikichi’s pants anonymously in the mail & leaves Shonan. Rumours of Yagyo Atsuki begins to fade and he is never heard from again.