|Also Known as||Sensei|
|Hobby||Collecting music scores|
|Special Skill||Inventing things|
|Physical and Vital Statistics|
|Manga||Volume 1 Chapter 1|
He is very enthusiastic about music. He has collected all kinds of music scores and they are really important for him.
He comes from a wealthy family, with a sharp mind and was taught the basics of music since he was a child. He has a lot of western knowledge and has invented a lot of speakers and small amplifiers.
He came from Choshu with Shinsaku in search for Shoin. When they saw that Ryoma got the guitar of Shoin they thought Ryoma might know something about the location of Shoin, but he doesn't. Later on they discover that Ryoma has the Peace Soul, so they get the know each other and slowly become friends (although Shinsaku doesn't think that way).
Later on he get's worried about something, but doesn't want to tell the rest of the band about that problem. He can't seem to put his feelings into words. At the concert of the Shinsengumi where the band was getting attacked by Soji, Katsura felt he had to do something to save everyone. The drums were calling for him, but he thought he wouldn't stand a chance against Heaven's Song, he didn't have the strength. That's when he heard the voice of Shoin who told him that Rock isn't about strength, but about having a passionate soul. With Passion, you can change the world. After hearing those words he goed to the drums and starts playing a song and afterwards his Peace Soul activates.
A couple days after the dead of Kondo. Yataro comes and tells them Shoin will be giving a concert tomorrow. At the concert Shoin really appeared, but the music he plays isn't his usual rock and it's starts hurting the bands ears. Katsura suggests it must be an impersonator, but Kaishu tells them it really is Shoin. Shinsaku climbs on the stage and sees it confirms it really is Shoin. Then the shinsengumi appears and they start to attack the band. But Hijikata comes and protects them and says the music Shoin is playing is the Heaven's Song and Ii is behind this. The music is getting worse, but Soji appears and he starts singing. Then the band hears Shoins inner voice asking the band to release him. Shoin is being forced to sing Heaven's Song. The band decides to release Shoin's soul with their song, and Soji and Hijikate help them. Shoins soul leaves together with his body and says his last words "Good bye, my beloved apprentices". At the end Hijikata and Soji join the band.
~Later on the anime~ Ultra Souls hears about the Heaven's Song Festival and the plan behind it to control the whole nation who hears the song and they would use the speakers to make everbody hear it. Kaishuu gives them the order to stop the festival by interfering when they start to sing the heaven's song concert and play rock instead. Although Shinsaku and Ryoma aren't with them anymore (see Episode 11) they want to continue the plan since this may be their last chance.
At the concert Ultra Souls was being overwhelmed by the heaven's song. They also introduced a new government group called: 'The Shinsaku & Kiheitai'. Shinsaku was the leader of the group and was under the control of Ii. At that moment Ryoma arrived. He apologized to Shinsaku and even though Shinsaku pointed a gun towards him Ryoma didn't back down and got the old Shinsaku back with the power of his Peace Soul. They started playing all together again and got the people who were under the control of Ii's magic back. Although Ii tried to get in their way with his magic, Yoshinobu stopped him with even greater magic.
The castle turns into a big speaker and Yoshinobu makes his official appearance as the 15th shogun of the Tokugawa Shogunate. He was first seen as a boy who helped out Ultra Souls from time to time.
When Katsura asked why he helped them he answered: "I was unable to do anything I wanted and was bored. I wanted to see the Ultra Soul which is said to have the power to change the world. I wanted to see if it could change my monotonous and borind days." After Ryoma saw that Yoshinobu was crying he knew he had to help him.
Thanks to Katsura they managed to get into the castle, although they had to leave him behind. In the castle Soji, Hijikata and Shinsaku were also left behind to make an opening for Ryoma.
At the end Ryouma saves Yoshinobu and everybody was still alive and a new era of rock started.
Katsura once ran away from home without telling anyone. Apparently, he was pretty worried when he learned about the betrayel of his schoolmates.
- He dislikes to eat black things.
- His favorite food is acorns.