Shoukaku Choyo
The 24 year old bearer of the Renjou (廉貞) mark. He is the teacher of the current emperor Taigatei. Usually seen smiling and basically a calm person, under that exterior he is actually a tactician that resorts to any means to keep the Ken Empire going. Any unknown action he takes is usually for the good of the Ken Empire. The Renjou mark is at his right palm.
In the anime, it is revealed that he is actually afflicted with some sort of fatal disease, and expects to die soon.