Rokou Cho is the older brother of Nuriko. He guards the jewel that contains Taka's memories saying that because it was the only treasure Nuriko and Korin left for him. He makes his appearance in the last 4 volumes of the manga and in the 2nd OVA.
Rokou's appearance was commonly misidentified as his hair color was originally purple but in some appearances, it was colored blue. His skin complexion was also misinterpreted due to shadows, but he was pale, much like his siblings. He strongly resembles both of them, and Nuriko would've probably resembled Rokou even more if he had lived longer.
During the day, Rokou wore a fashionable kimono, most likely because his parents own a prosperous fabric emporium in Eiyou, and his hair was traditionally tied. In the night, he wore a loose light blue shirt and his hair down.
- "They said you died honorably. They say you peacefully rest in the snow. But why? Why can't I bring myself to accept the fact that you're dead?"
According to Nuriko, Rokou was a coward-- a wimp who always depended on others. Reasonably, Rokou had a hard time accepting the deaths of his siblings, and as the eldest of the Cho family, he was expected to be the mature and stronger one. In reality, the shy and weak Rokou was relentlessly bullied for his lack of conviction and both of his siblings were always there to save him. He found strength in Buddha instead of the Beast Gods that took his brother away. He coveted the crystal ball which contained Nuriko's memory jewel and propped it up on an altar, seeing it as his only connection to his late brother.
Beyond his aggressive front, Rokou is a deeply sad and broken young man who, in true Cho fashion, refused to let go of his loved ones due to the immense pain it'd bring him.
- "I wanted to prove to you and show you that I could be a big brother to you. But before I could you were gone!"
Rokou did make a brief appearance in Nuriko's light novel: Yukiyasha Den. At the end when Nuriko was passing through Eiyou on his way to the imperial harem, he spotted Rokou in the crowd. He pondered over whether or not he should approach him but ultimately, he made the choice to stay silent.
He first officially appeared at the end of the second episode of the 2nd OVA, when a maiden was calling his name as he watched over the ball with the memory jewel. Chichiri and Tasuki attempted to explain the situation, but Rokou refused to give up the precious object.
With the jewel located but no means of retrieving it, the warriors broke into Nuriko's house a week later. When the memory jewel was in Taka's hand, a demon suddenly possessed him and Rokou woke up, seized the ball, and ran to a temple to protect the keepsake. Inside the temple, while he was praying, Nuriko's armbands appeared before him and used his spiritual strength to knock Rokou out and haul him and the jewel back to his home.
Rokou witnessed the power of the Suzaku Seven as they fought to defeat the demon in Taka. Nuriko's soul pleaded that he would help retrain their friend and after he refused, Chiriko attempted to possess him but failed, as his heart was not open to him. Just when Taka was about to bite his tongue because of the pain, Rokou held out his arm so he could bite him instead. Suddenly, he could see Nuriko and the two reunited after years apart.