In a world rife with radiation, disease and escaped medical experiments, mutants are a reasonably common sight. Most lead ordinary lives, contributing to and prospering in whatever society they happen to be born into. Others may be less fortunate.
It's worth pointing out that being a mutant carries no general social stigma in the world. Being a mutant is considered normal, having a problem with mutants generally is not.
Famous exemptions from this would be Nova, well known for their irrational hatred of mutants.
A so-called notorious mutant have very little to do with upstanding citizen mutants described above. A notorious mutant is a creature characterised by physical prowess, emotional instability and a seeming constant need to attack everything around them. They are a danger to themselves and others Most wayfarers pay careful attention to stories and rumours of notorious mutant activity and do their best to stay away from areas they are said to roam.
Notorious mutants of legend and note.