The True Nature Of Yushiro's Existence: Mortal Or Demon?

He was in a weakened condition battling an illness when tamayo offered.

Webit's pretty bad but kokushibo still ended up accepting his fate, i'd say the demons who died full of anguish and regrets, like enmu, kagaiku and even muzan had a worse death.

Webin demon slayer chapter 15, tamayo gives an explanation that could help fans understand how yushiro is an exception to the aforementioned rule.

Webyushiro is a key supporting figure in “demon slayer:

Webyushiro was a human being in tamayo's guidance, as she worked as a medical practitioner.

According to the concluding chapters of the manga (chapters 204 and 205), both.

Demon Slayer: How did Yushiro survive after Muzan Kibutsuji died? Explained

Webyushiro is a demon of unknown strength, although living for a long time under tamayo, who is herself a deceptively strong demon who could severely weaken muzan, it is.

Webas lady tamayo’s travel companion and a trusted ally of tanjiro kamado, yushiro underwent demon transformation at tamayo’s hands due to a terminal illness.

Webby the end of the manga, yushiro is the only one left alive of the original group who remembers what happened with the demons and demon slayers.