Kachou Ouji  

課長王子, The Legend of Black Heaven

Oji Tanaka was a salary man living in Tokyo with a wife, child, and mundane job. However, life wasn't dull for him as he had been known as "Gabriel" and led the heavy metal band Black Heaven 15 years ago. One day, he received an invitation from a mysterious blonde woman named Layla to showcase his legendary guitar skills once again. He didn't know that his music would generate power for a massive weapon in an intergalactic war.