Shinrei is an ex-member of the Goyousei who has great loyalty to the Mibu Clan. He hates Kyo for abandoning the Mibu and ruining their plan for domination. He dislikes Hotaru (Keikoku), as the latter always provokes him and has no loyalty to the Mibu.
The eldest son of a noble man of the Mibu and his official wife, Shinrei was the rightful heir of his branch. He has been taught to be totally loyal to the Mibu and has devoted his life to them. He has a cold and serious personality; though sometimes he loses his cool easily, especially if he is provoked by Hotaru (Keikoku), his rival and half-brother.
Shinrei was told about his relation to Hotaru in his youth. After learning that fact, he has kept his eyes on his little brother from the shadows. It was Shinrei who stopped his father from sending assassins to kill Hotaru and who secretly helped Hotaru participate in the competition for a position in the Goyousei (which is only open to competitors from noble families of the Mibu). However, he never showed himself as Hotaru's brother until his last fight with Hotaru and Kyo.
Despite their contradiction and contrast, Shinrei and Hotaru hold a strong bond between them, but they consider each other as siblings and rivals. After their final bout, their bond becomes stronger and the two even start to fight together.
Shinrei fights with a "dancing sword technique" as his fight looks much like a dance. The technique is dangerous and nearly overwhelms Kyo. Being of incredible skill, Shinrei's abilities increase as the skills of his opponent increase. The technique is based on a seemingly simple, but rather impossible, practice. He first slashes, and his opponent moves accordingly to counter his attack. While his opponent is moving to counter his attack, Shinrei redirects his attack with near impossible speed so that although it appears as if his opponent is blocking, that opponent will actually get hit instead. This is soon countered by Kyo who simply closes his eyes and "senses" Shinrei's blade. Shinrei was trained personally by Fubuki.
Shinrei's father is the founder of the Mumyou Saikyou Ryuu School of Water, so Shinrei controls the element of Water. After Kyo defeats his Dancing Sword Technique and wounds him, Shinrei forms a sword out of his own blood. His ultimate technique is the Mumyou Saikyou Ryuu, the Seven Water Split Dragon.
Shinrei's left eye becomes red in moments of great stress, in contrast to his younger brother.
In the end, it appears that Shinrei becomes the "leader" of the Mibu Clan and rebuilds it along with Yuan's family and the creatures from the forest. In the bonus chapter, it is revealed that he started performing with his water dragons in the rebuilt Water Dance Stage.