Why is Nezuko stronger than regular demons? In manga #83 it is mentioned that


   Nezuko's regeneration speed matches that of an upper moon, and later it's mentioned that it surpasses the regeneration speed of one of the upper moons


Also, Nezuko has shown to be stronger than an average demon before, when she kicked those strong demon balls for example. Why is Nezuko stronger than regular demons, considering she neither has martial art skills, nor consume humans to get stronger?
It was referenced by several demons (starting with three-horned demon with clones), that she seems to be strong due to amount and quality of demon blood she was injected with to be turned into a demon. Other possible reasons were not specified so far.