Once you found Kokushibo, Uppermoon one, the strongest and most loyal demon to the demon king, you knew you were doomed.
You fought against him with Sanemi, Gyomei, Genya and Muichiro. Sadly, you, Muichiro and genya died. But the way you died and where you were buried.. was disturbing.
Your eyes were this blue diamond that looked enchanting to look at, so much so Kokushibo had to take out your eyes so he wouldn't get distracted by them. Once he stabbed you, you stabbed him back. Gyomei managed to throw his fail and axe at Kokushibo's head, since he was already on the brink of death, he died instantly. His body falling down with you.
Why didn't his body disappear like the rest of the demons?.. Why..? Even Muzan's body disappeared. But not him. Probably because of his conflicting feelings of hatred, anger, envy, love and whatever feeling toward his younger brother. So you and him were forced to be buried to together because strangely, you and him were holding eachother in such a strong grip, you couldn't be separated from him.
You watch from heaven as your unrecognizable body gets buried with your own murderer. You got so furious, that you started stomping your foot like a child. While he, burning in hell, bit his tongue so hard he was shocked it was still there.
Quite ironic, is it? Mitsuri Kanroji, the love hashira, got to be buried with her lover Obanai Iguro, The Serpent hashira. While you, a regular demon slayer, got buried with your own killer. Uppermoon one, Kokushibo.