Meet Arcturus. He is a prodigy eevee. He contacted a genetic defect that prevented him from evolving, ever. But in exchange of that, Arc had Intuitive Aptitude ability which enable him to understand complex matters in seconds.
Unfortunately, Arc used his gift to build a criminal empire. He didn’t care how many mons he made miserable with the crime syndicate’s activity. He was rejected by the world thanks to his defect, and so he rejected the world itself.