Ryōku (リョク, Ryoku) is a young male from the Village of Shin, located in East Asia. Ryōku, like the rest of his village, share a hatred for the Star Clan and its members. He was controlled by Masamune until ironically being saved by Black☆Star.
Ryōku is one of the most level headed people in his village appearing as calm and collected through most occurrences, except when it comes to his fear/hatred of the Star Clan. Ryōku is fearful of their power and their ways of battle, even losing self confidence in himself while comparing himself to Black☆Star. Overall, Ryōku maintains a cool head as the base of his personality.
Ryōku's appearance consists of a pewter colored bandana wrapped around his blackish hair, along with his outfit being a two tone blue shirt with green designs on it. He has bronze eyes. Ryōku wears dark blue shorts with his kimono top tied around his waist which his colored of a violet shade and having geta on his feet. In his Uncanny Sword mode, Ryōku's skin becomes pale and his hair lightens a shade. The markings of the Demon Sword appear on his face and his pupils become red as his sclera becomes a rust color.
On his own, Ryōku doesn't have any outstanding talents except from when Masamune performed the Soul Possession on him and gave him the power to perform Masamune's moves. However, Masamune is in complete control over him and his body.
Shadow Puppet: Shadow Puppet is a shadow type move Ryōku performs under Masamune's whim to strike Black☆Star, although he only performs one, the single puppet transforms into a Puppet Thrust.
Puppet Thrust: The 'Puppet Thrust' technique comes about when Masamune Ryōku forms his Shadow Puppet into a slender figure and fires it into Black☆Star. The spines from the puppet can branch into smaller ones.
When Tsubaki Nakatsukasa and Black☆Star arrived in his village, it appeared that Ryōku and/or his village had had dealings with the Star Clan or knew of their reputation in the past as he and the other villagers recognized the tattoo on Black☆Star's arm. At first believing that Black☆Star is part of the Star Clan, he offers him money to leave before chasing him out of the village for fear he may attack them.
Later on, Ryōku is seen hiding in a barn plotting to to kill Black☆Star for revenge, as the Star Clan murdered his mother and father. Despite this, he is still terrified of the Star Clan, and is suddenly approached by the Uncanny Sword Masamune. Masamune rambles about his own hunger before commenting on Ryōku's fear and offering to make it go away. Having tricked the boy into becoming his meister, Masamune possesses Ryōku's soul and begins to terrorise the village, before Black☆Star and Tsubaki show up.
Masamune possesses Ryōku's shadow and uses the two of them to fight with Black Star but when Black Star channels his wavelength into Ryōku's body, Masamune is forced out of his body, freeing him from possession.
After Masamune is defeated, Ryōku comes to realize that Black☆Star was not a member of the Star Clan but that still didn't mean that he liked him any more than before. In the anime, Ryōku said that if Black☆Star was not a member of the Star Clan, he would come to like him (with a smile on his face).
- 'Ryōku' means strength or power (力).