| "How Small."|
Hao calls this article small.
|First Appearance:||Chapter 1|
|Japanese VA:||Nobutoshi Canna|
|English VA:||Marc Thompson|
Muscle Boy (マッスルボーイ, "Massurubōi") is a member of Umemiya Ryunosuke's Gang and is his adviser.
Muscle Boy wears a red wool hat, shorts and an orange jacket with an M (for his nickname) on the left sleeve.
Meeting with TokagerohEdit
Muscle Boy takes Ryu and the gang to the abandoned Funbari Bowling Alley asking him if they can make it their new best place. However, Ryu refuses because it is too far from the train station and there are no convenience stores nearby. When Ryu is possessed by Tokageroh, he tells his gang to break into the museum and steel Amidamaru's Harusame. however, Muscle Boy refuses because that would make him a burglar and ends up getting stabbed in the leg by Ryu. Ball Boy helps carry Muscle Boy to Yoh's House so they can stop Tokageroh from killing Manta.
Shaman Fights in TokyoEdit
Before Ryu goes to America, Muscle Boy and the others write him a farewell card.
Travel through AmericaEdit
Muscle Boy is mentioned by Ryu claiming that anybody that looks like him may not be a bad guy after meeting Chocolove.
In the English version of the anime series, the scene when Tokageroh possessed Ryu and stabs Muscle Boy in the leg was however edited out.
- According to the Character Files, Muscle Boy has ten siblings
- Ryu claims that Chocolove McDonell looks a lot like Muscle Boy because of their lips