In Tokyo, there is a music girl training system

(Holy Armor: This book is about the modern Tokyo world view of Zongman, involving MyGO, I recommend, Lonely Rock, etc. It is also a harem story for the male protagonist, so don't read if you don't like it.)
Lu Yu, seventeen years old, is handsome and has excellent character and academic performance.
After traveling to a hodgepodge world of Tokyo-style anime, Sagi got a system that can train heroines from various worldviews to become masters in the field of music and help them solve their problems.
Thus, Lu Yu began his journey as a gold medal mentor.
Hoshino Ai, Toyokawa Shoko, Goto Ichiri...
One after another, the girls overcame difficulties and achieved success with Lu Yu's help. However, when the girls became successful and wanted to repay him, he had already hidden his fame and left quietly to go to the next heroine.
"You said I was the best idol in the world, so why did you leave?"
"We agreed to form a band for life, how could we allow you to escape?"
"I won't let you escape. I will find you even if I have to chase you to the ends of the earth!"
Lu Yu: “???”
It's just a system task, don't take it seriously.