- "Even if I were to turn my back on him, he'll probably smile and forgive me again."
Background and bond with Uruki
- "Then he smiled. Smiled to the man who was about to betray him."
- —Soruen about Uruki
Uruki's mother had entrusted the infant to Soruen's father, Tauru, and Soruen. They raised Uruki while living on the run, avoiding the assassins who were sent to kill the outlawed crown prince. Soruen and Uruki grew as close as brothers.
When Soruen was 21-years-old, Tauru died defending Uruki from assassins and told Soruen to protect Uruki with his life. Mentally fragile after Tauru's death, nine-year-old Uruki decided to jump off a cliff. Soruen held on to Uruki, but was tempted to let go of the boy so he could live a normal life. However, realizing that he needed Uruki as much as Uruki needed him, Soruen saved the boy's life and vowed to remain by his side. Since then, he has always appeared when Uruki has needed him and they are able to find each other using the scent of the Toka seed, which both men carry all the time.
Soruen uses a sword for battle and well as gunpowder. He protects Uruki with his life, but when Uruki is injured, Soruen is additionally a skilled healer who uses bandages and medicine.
Soruen has pale skin complexion and black hair. Mostly seen very serious, he has narrow eyes and most of his hair is blocked off his face.
Although Uruki and Soruen grew up together like brothers, Soruen acts more like a retainer and is always there when Uruki needs him, until when he sacrifices himself at the Oroko Valley for Takiko and Uruki's reunion and safety against the Kutou soldiers.
Soruen makes an appearance at the prequel, following Uruki's. He is very crucial to Uruki and his relationship with Takiko, as he is the one who encourages the both to acknowledge their feelings. Soruen appears in the most critical moments, and it is repeatedly shown that he saves Uruki's lives countless times. Though he is only viewed as an aid to the Genbu Seven, he is the very effective communicator and mediator between everyone.
Main article: The incident in Oroko ValleySoruen protects Uruki with his life until he sacrifices himself at the Oroko Valley to ensure that Takiko and Uruki are reunited and neither is captured by Kutou soldiers. He leaves Takiko with his Toka seeds so that she will share the same bond he held with Uruki. Soruen's death devastates Uruki and he is only able to overcome his grief when Soruen's soul is properly sent to heaven with a Hoshikaeri (lit. return to the stars) ceremony.