I know it's from like dead monsters but how in the heck can people use it? Is it an organ or something? I would say something like dna but that doesn't fit either. Does anybody know what exactly it is or does from a lore perspective?
A mutagen is an agent which causes rapid genetic mutations to occure, usually to ones DNA. For example radiation can be considered a mutagen as high doses can cause mutations. However, most mutations cause cancer rather than give you superhuman abilities. In fact Witcher cell's are kinda like cancer cell's, as they can live pretty much forever, only it is a rapid evolution which is not harmful to the body.
