I'll briefly explain why the author wrote the legendary story of Tibetan opera, and then write it down.

There are many reasons for writing a legendary story of Tibetan opera, but the most common one is to show the charm and uniqueness of Tibetan opera culture through this story. The author might consider his interest in Tibetan opera culture or hope to express his love and respect for Tibetan opera culture through this story. The author might also consider the motives of the story from a social and cultural perspective. He hoped that this story could attract the public's attention to the Tibetan opera culture, so that more people could understand and appreciate it. He also hoped to explore the status and significance of Tibetan opera culture in today's society through this story. There may be many different ways to write a legendary story of Tibetan opera, but the most important thing is to show the uniqueness and charm of Tibetan opera culture through this story, so that more people can understand and appreciate this traditional culture.