Shiroyama serves as one of Kanzaki's most loyal and devoted underlings. Although he is a strong delinquent, he was nonetheless easily defeated by Oga with a single shot to the chin. Even after the dissolution of Kanzaki's gang, he has become attached to Kanzaki and continues to work for him and act as his voice of reason.
Shiroyama was created by Ryuhei Tamura as a minor character but he has been getting more screen time in the anime.
Shiroyama is a heavily built man with two parallel scars on his left cheek. However, he also has two braided ponytails which adds an emasculating feature to his macho image.
When Shiroyama made his first appearance, he was depicted as a strong and intimating delinquent but this image was easily crushed when Oga wiped the floor with him in an instant. Nonetheless, despite his defeat he has been shown to be very loyal to and hold great respect for Kanzaki even to the point of jumping out the window on his command and dressing up as a baby (in the anime) to help him get stronger than Oga. He has also displayed notable fearlessness and male honour when he defended two of Kunieda's subordinates from a group of students of Saint Ishiyama Academy and willingly took damage from the weight equipment they threw at him, which landed him in the hospital.
Major Story Arcs
Ishiyama High Arc
Shiroyama is first seen when he blocks Oga from approaching Kanzaki and asks what his business is with the man. Furuichi replies for Oga and states that Oga wants to join Kanzaki's gang to which Oga concurs (in a less than respectful manner, to Shiroyama's dislike). Curious and intrigued, Kanzaki grants him membership but Shiroyama protests, arguing that he can't be trusted and that he must prove to them that he's worthy of being part of their group. Kanzaki then tells him to put Oga to the test and that if Oga wins, he's permitted to join them. Shiroyama agrees to the condition but right when he was about to attack Oga, the latter easily defeats him with a single shot to the chin. Kanzaki rises from his seat and applauds Oga's victory but Shiroyama wills himself to stand and states that he's not out for the count just yet. Kanzaki replies that he's finished but Shiroyama retorts saying that he can still fight and that he'll do anything to show that he's worthy. Amused, Kanzaki then commands him to prove his loyalty to him by jumping out the school window. Somewhat hesitant, Shiroyama finally agrees to do so, but before he gets a chance, Oga knocks Kanzaki out the window first, shocking everyone in the room including Shiroyama.
St. Ishiyama Arc
After being transferred to Saint Ishiyama Academy along with everyone else from Ishiyama High, Shiroyama was sent to a hospital following an encounter with some of the new students. According to Hanazawa and Asuka, Shiroyama tried to stop a group of boys from harassing them but to his mistake they were only trying to ask them out on a date. To make it up to them, he allowed each one of the three boys to punch him once but instead, they each threw one piece of exercise equipment at his head, with the last being the largest and most dangerous. Later, he reappears at a volleyball match between his friends and the Horsemen despite the blood that was gushing out of his head. He was then removed from the court and taken back to the hospital.
Demon Invasion Arc
After Shiroyama made a fully recovery, he, along with his friends, are seen aiding Furuichi and Lamia in search for Beel's bother, En, by helping them beat him at an online video game, though Shiroyama played a minimal role since he lacked the skills necessary to play and win.
Powers & Abilities
Shiroyama is shown to have notable fighting abilities but in comparison to Oga and Kanzaki, he still lacks potential. However, he is quite durable as shown when he managed to stand after being knocked down by Oga and when he withstood assaults involving weights being thrown at him (not including the last and heaviest one that led him to a hospital).