Honestly, it's so refreshing to find out that this wasn't your typical reincarnation story line. Both Mayuki and Kotofuji were different people from the past Kotofuji and Tsuguyasu. Kotofuji may not be a god, but he is still an undying supernatural being, which is pretty sad in and of itself. Mayuki will one day still leave him behind as a mortal being. It seems like he wanted to erase himself from existence after he thought he couldn't be with Mayuki anymore, I can't imagine how he will take Mayuki eventually leaving him behind.
Honestly, it's so refreshing to find out that this wasn't your typical reincarnation story line. Both Mayuki and Kotofuji were different people from the past Kotofuji and Tsuguyasu. Kotofuji may not be a god, but he is still an undying supernatural being, which is pretty sad in and of itself. Mayuki will one day still leave him behind as a mortal being. It seems like he wanted to erase himself from existence after he thought he couldn't be with Mayuki anymore, I can't imagine how he will take Mayuki eventually leaving him behind.