The answer is actually in the game, in a voice line by the shopkeeper.
They should be called "Mystics"
Relevant line: "I don't know what this does but [..] all the mystics are buying it"
It also makes sense from a setting perspective, the world of Deadlock is quite similar to our own but the rift has caused changes to only a few individuals. Of course normal people would consider these individuals mysterious, and hence call them Mystics.