User blog comment:Kogath/Monster Hunter Generations Discussion/@comment-28908045-20160806121521/@comment-11537809-20160806204127

Well, a common trait of the variants seems to be that normal variations can turn into those variants naturally (Raging Brachy iirc is just an old Brach with slime that has further covered its body and became more volatile, Savage Jho is just a really really hungry Jho, Chaos Gore is just a Gore that failed to mutate, Rusted Kusha is simply an old Kusha with rusted skin and has not shed), where the interference of hunters is not really a necessary prerequisite.

Meanwhile, Deviants seem to be emphasised to be monsters that have survived hunts and as a result are battle-hardened individuals with abilities that surpass those within their species. The classification of something as a Deviant seems to require it to have fought hunters in the past victoriously. While on the surface, the appearance of variants may be like deviants, the reason behind it seems to be much more different. Correct me if I missed anything or if I made a mistake.