Webat the start of demon slayer, nezuko kamado is 14 years old.
She plays a crucial role in the story as the younger sister of tanjiro kamado, the main protagonist.
Webthis means that, in the present timeline of the anime, she is technically 14 years old, even though her body remains unchanged.
Nezuko finally begins to age once.
Webafter returning to her human form during the infinity castle arc, nezuko finally starts to age.
With the help of tamayo’s medicine, she becomes the first demon.
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.