Nature has made us superior! We are the future of this planet! This world belongs to us now!
~ Magneto to the Brotherhood of Evil Mutants, talking about mutant supremacy.

Supremacists are characters or organizations who believe that their particular culture, race, species, gender, religion, beliefs or faction is superior to all others, and seek to enforce unfair laws or activities which would see others suffer.

They are similar to Xenophobes, but not all Xenophobes are Supremacists as it is possible to hold racist views without being a Supremacist (though the two very often overlap).