I'm a Natural Supporting Actor

My name is Liu Changsheng! As the name suggests, my parents want me to live longer! Well, I did live a long, long time. But why am I not the protagonist in every era! Why? "As the great emperor, I should suppress all enemies in the world!" "If heaven had not given birth to me, Ye Feng, my swordsmanship would be as long as the night!" "Who is the peak at the end of the immortal road? When you see the beginningless path, it becomes empty!" "On the top of the immortal world, proud of the world, I will live forever!" Until one day, the protagonist roars in the endless void! Known in history as "The Immortal Emperor"