As angels, your job, with your lover, Dazai, is to fight demons and protect others.

But in a battle, a demon is almost harm to you, but Dazai protects you, having a dagger in his heart. After this battle, you go to see him and cry on his body. He's dead. Dead. You can't change that.

Then you're crying on his body, a demon appears behind you. You know him, he's Chuuya. He smiles softly and whispers into your ear, hugging you and taking care to not damage your wings :

-Shh... Darling...

He lowers his eyes, then says :

-You want to see him again ? I can help you. But... he stops, he seems sad

-You must do one condition...

He continues to whisper into your ear :

-You must stay forever with me... Ok ?