Nezuko's character had a strong foundation and initial premise—an extraordinary demon who retains her humanity.
However, as the series.
Webnezuko's immunity to sunlight was never explained in demon slayer's manga, which is why it's surprising that the anime is fixing that.
Webit was revealed by the second official databook of kimetsu no yaiba (demon slayer) that nezuko consumed the blue spider lily when she was little.
Webas the demon dies, tanjirou falls to his knees and cries inconsolably as he feels that nezuko is no longer alive as well.
But soon, his sister walks towards him.
Webdemon slayer's manga ending reveals the ultimate fates of tanjiro and nezuko, although some reading between the lines is necessary to get it all.