The Sakura Tunnel ~Promise of the Dragon's Light~

From the acclaimed dark romance epic
"The Dragon's Heir: Compass of Light and Darkness"
by Twilight Master Comes a breathtaking J-POP ballad born straight from the novel's most emotional climax. In the final act, the protagonist Yicheng - once a cold-blooded "dragon" who deceived heaven itself - finally keeps his one-year-old promise.
Together with his true soulmate, Yuki, he rows a small boat beneath the breathtaking cherry blossom tunnel at Chidorigafuchi, Tokyo. That single, serene moment of pure love after twelve years of war and monstrosity has been transformed into the ultimate 90s-style Japanese love song:
"The Sakura Tunnel ~Promise of the Dragon's Light~" On the surface, it's a tender, heart-melting pure-love ballad anyone can fall in love with.
But readers of the novel will feel the hidden depth - the single hot tear sliding from the dragon's icy eyes, the last remaining spark of humanity that refuses to die. "I want to protect this smile forever."
"I never want to let go of this ordinary, irreplaceable happiness. "The cherry blossoms become a tunnel of redemption - the light at the end of twelve years of darkness. If you've read the book, this song will hit you like a wave of emotions.
If you haven't - listen first, then open the novel.
https://ncode.syosetu.com/n2083ll/

You will understand why Yicheng risked everything... just to keep one simple promise under the Sakura.
Twilight Master "The Dragon's Heir: Compass of Light and Darkness"