Webtamayo’s demon blood art involves using her own blood to affect other people.
She can create truth serums or hallucinations.
Webmuzan kills tamayo, and later nakime when she is hypnotized by yushiro to use her powers against him, but he is forced above ground by the corps.
Webtamayo becomes an expert in demon physiology, develops a drug to weaken muzan, and sacrifices herself in the final battle, ensuring a world free from muzan's reign.