Demon Slayer: on the Verge of Death? Become a Ghost!

[Time Travel + Demon Slayer + Both Good and Evil] Traveling through a demon-destroying world, the entire clan was brutally exterminated. Fortunately, he survived, only to learn that he was infected with a disease and was about to die soon. Fortunately, he met a cursed medical descendant... Drink the elixir of longevity and become a special ghost king! Simulate vampire magic and create a new legend! Redeem the ghost of Shangxian and change the fate of Zhu Mie! After Shangxian was redeemed, the lonely ghost Tsuji Muzan said: "If I swallow you, I will be the strongest in the world!" Kubo Nagakawa: "Come and eat me."