Sanjuro is a Heavy Blade modeled after a Ronin, or wandering Samurai. He is a rugged looking warrior of indeterminate age who wears dark platemail on his upper body, and a Hakama (a sort of Japanese skirt) around his legs. His wave symbols are visible on part of his face, as well as on his clothing. He has an eyepatch over his right eye. Since he is modeled after a Samurai, he exclusively wields Katana type weapons. Sanjuro tries his best to act the role of the wise and honorable warrior. And sees himself as a sort of wandering hero, traveling throughout The World protecting the weak. He has a great deal of hate for PKers, who he considers "honorless dogs". He is especially helpful to people visiting the JP servers from English speaking servers. Though he was still a bit of a newbie in his first appearance, his encounter with Kite and his assistance during the Twilight Incident made him into a very powerful player. He is likely one of the most powerful Heavy Blades in the game. He is close with most of the .hackers and a very good friend of Hotaru, who considers him as a mentor.

Sanjuro is actually a Japanese teacher from South Dakota. He plays on the JP servers of The World in order to improve his skill at the language by speaking with others who are fluent in it. Sanjuro is a major character in the Legend of the Twilight Anime. He first appears when he is forced to save Shugo and Hotaru from a group of monsters they ran into while searching for medicine for Hotaru's Grunty. Though he mistakes Shugo for Kite at first, he quickly realizes his mistake. Later he is sought out by Balmung who asks him to train Shugo, as the Twilight Bracelet he received from Aura will be needed to help bring balance back to The World. Sanjuro accepts and takes Shugo on as an apprentice. He also assists Shugo in many of the battles that occur later in the series.