Monochrome Factor Ryuko
Name Ryuko
Kanji 劉黒
Romanji Ryūko
Race Rei
Gender Male
Height 184 cm (6'0)
Weight 68 kg (149 lbs)
First Appearance
Manga Debut Volume 5: Chapter 25
Anime Debut Episode 24

Ryuko (劉黒 Ryūko) is the former Royal Direct Rei King, former counterpart to Shirogane, and the predecessor of Akira Nikaido.


Ryuko has fair skin and long black hair that reaches to the ankles. He bears resemblance to Akira, except that Ryuko has red eyes in color, instead of a grey/green like his successor. He wears a white cloak with black trim over a long coat with red and gold trim. Ryuko has six armbands on his wrists, three on each wrist, and wears black gloves. He is also shown with two belts across his waist, black pants, and black boots. The weapon Ryuko carries is a silver scythe with a transparent blade. It also has a magenta/pink sash hanging off of it. He is 184 cm tall and weighs 68 kg.


Like his reincarnation, Ryuko is generally easy-going and very laidback ie. being over an hour late to a meeting with Shirogane. Other times, he is more serious, ie. when training with Kou. Ryuko is also wise, giving Kou advice on being a bit more tolerant of Sawaki. But it is also implied that he is a bit naive by Shisui.


He was murdered by Homurabi before Akira was even born. Although he has yet to awaken in the present time, and his memories continue to remain sealed within Akira, he has awoken once before, during the time Akira and Kengo Asamura first met Kou. Because Ryuko had not fully regained his strength, he was unable to remain in his Rei form for long, although he defeated Kengo with relative ease. Before he reverted, he told Kou that he never thought of Kou as a betrayer from the beginning, and told him to "repent" by protecting Akira if he still felt guilty about abandoning him. In chapter 54, it was revealed that he was purposely killed by Sawaki by the order of Homurabi.


  • Ryuko was featured on the cover of volume 9.

Ryuko on the cover of Volume 9

  • His favorite animals are birds and cats. He prefers classical music and his favorite colors are red and white.