A Phoenix on the Ninth Floor of Heaven(2019)

Feng Yu Jiu Tian

On his way to school, Feng Ming lost his life to save a child and somehow "transmigrated" into the body of West Thunder Nation's Crown Prince in a different universe. However, this Crown Prince was not as highly respected as Feng Ming expected; moreover, he seemed to be in an unusual relationship with Prince Regent, Rong Tian. Later, Rong Tian realized that the Crown Prince actually harbored a different soul in his body. Coupled with the incredible ideas Feng Ming would blurt out sometimes, Rong Tian started finding Feng Ming more and more interesting…

(Source: Bilibili Comics)

Note: Chapter count includes a prologue.