Tegiru Rowun is a character who appears in the sequel Fushigi Yuugi Genbu Kaiden, where he is a major antagonist for a period of time. He is the emperor of Hokkan after his brother Temudan Rowun, and before his nephew Limudo Rowun.
Tegiru is the younger brother of Temudan Rowun, and second-in-line for the Hokkan throne. In Chapter 35's significant flashbacks, it was revealed that he and his brother went hunting together, and on the process they came across the monster that inflicted his brother with the "incurable disease", changing the fate of Hokkan forever.
When their father, the emperor, learned of his eldest son's sickness, the fortune teller delivered a false fortune to the Rowun family, (after she was paid) and said that Temudan was never going to recover (but in truth, he did, and he could). Hence, the throne was given to Tegiru, and he ruled for many years while Temudan was exiled to a castle at the back of the palace.