Tuan was the first Yu-Ti and ruler of the mystical city of K'un-Lun. During a ritual performance of the dragon riders, one of the dragons went berserk and attacked Tuan. Quan-St'ar intervened and saved Tuan's life by slaying the dragon and cutting out its heart. Enraged at this action, Tuan banished Quan-St'ar from K'un Lun and revived the dragon by melting his heart and placing it in a sacred cavern.
Over twenty years before Iron Fist returned to Earth from K'un-Lun, Yü-Ti (Tuan) presided over the struggle between Davos and Wendell Rand-K'ai for the right to challenge Shou-Lao. He stopped the fight, declaring Wendell the victor when Davos refused to yield, despite taking a serious beating, and Davos accused him of favoritism. Later, after Davos had challenged Shou-Lao without permission, nearly dying in the process, Yü-Ti (Tuan) banished Davos, sending him to Earth, never to return, when the portal next opened.
After he died, he went to Feng-Tu where he became first among the Yama-Kings. He welcomed Heather Rand to Feng-Tu, although he was surprised at her presence as she was not a citizen of K'un-Lun. He was unable to stop Dhasha Khan's invasion of the afterlife. When Iron Fist came to Feng-Tu, accompanying Jade, Tuan cast a spell over him so the Bowman could kill him and force him to help them defeat Dhasha Khan. He led his troops alongside Iron Fist, Jade, and the Bowman against Dhasha Khan's men to reconquer Feng-Tu and prevent Khan from bringing the N'Garai back to Earth.
Meanwhile, his son Nu-An became the new ruler shortly after Tuan had passed away. However, Nu-An was corrupt, which led Thunderer to start plotting against him. Thunderer also had suspicions that Nu-An was behind Tuan's death.