The protagonist of Shamo. As a child he was considered a genius, until one day he snapped and stabbed his parents to death. After being sent to juvenile prison, he learns karate to defend himself.
Ryou Narushima is consistently depicted as being unrepentant for the murder of his parents and is shown repeatedly committing morally repugnant crimes such as assault and rape. Though capable of redemption (as evidenced by his care-taking of his sister and various small charitable acts shown throughout the manga) ultimately Narushima is depicted as a Byronic hero spiraling into darkness, his chances at reform slowly ebbing away as he gives in to more and more of his depraved and brutal tendencies.
A minor theme throughout the manga is society's morally-based stratification, how it condemns young criminals like Narushima, and how that condemnation forces Narushima to the fringes of society making his chances of true reform and redemption even more remote.
Various supporting characters within Shamo act as dramatic foils to Narushima, with Naoto Sugawara being the primary example of this. Famous, rich, and beloved for the same abilities that make Narushima a social pariah, Sugawara's presence can be seen as an example of society's cognitive dissonance towards violence. Narushima is reviled for his violent traits, while Sugawara is praised & rewarded for using those same traits in a slightly different context.
Ryou Narushima is modeled after two persons:
- Juvenile delinquency part: The "Youth A."
- Martial art part: Ryu Narushima (成島竜) of Kyokushin. This Karate fighter's name has same pronunciation as the main character's name.