In fact, it is purely because of the recent nymphomaniac German musical Elisabeth, especially the actors Uwe and Mate who play the Grim Reaper. One is noble and cool, the other is fanatical and violent, and occasionally has a little tenderness, which makes people drool.
Uwe really has a boyfriend who is officially living with him, so Usagi inevitably went too far and wanted to write about the feeling of two shinigami being together.
Fans of Uwe and Mate, please don't take pictures, it's just personal YY.