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, a powerful fortune teller hired by Tegiru delivered a false fortune to the Rowun family and said that Temudan was never going to recover (but in truth, he did, and he could: the true prophecy said that Temudan would die, but only when the Genbu Senshi were reunited). Hence, the throne was given to Tegiru, and he ruled ruthlessly for many years while Temudan was exiled to a castle at the back of the palace. Tegiru also keeps one half of the Urumiya twins, Teg, imprisoned while the other, Hagas, is taken away and ultimately serves Temudan.
Tegiru also rejects his daughter, Efinluka Rowun alias Firuka, solely due to being a girl. She ultimately runs away from the court and becomes a priestess.
When Temudan was officially enthroned after a rebellion, he had Tegiru imprisoned and bound. Later he had him brought forcibly to his presence and sentenced him to death - a sentence that Hagas carried out by cutting him up alive: his left leg was amputated, his left arm followed, then his left eye was torn out, and he ultimately was decapitated. Even in his middle of this gruesome execution, Tegiru refused to recognize Temudan as the Emperor, taunting his brother about the upcoming destruction of Hokkan until Hagas beheaded him.