Lots of them in FO1, decent amount in FO2, lots of them in Tactics, lots of them in FO3 and decent amount in FONV.
Don't see why we need more mutants really, if you want more then play the other games or go back to super mutant hot spots in New Vegas.
No reason for a DLC entitled to them exclusively. (Legion on the other hand needs one. :whistling: )
Well,
FO1- Most likely died in Mariposa and The Cathedral
F02- There were the few dummies that came from Mariposa's slave workers. But their status is unknown in lore.
F:T- Likely purged by the MWBoS.
F3- Since Vault 87 is for all intents and purposes purged. I don't see how the Eastern Super Mutants will carry on for more than a few decades. Especially due to to their deeply mentally crippled issues.
F:NV- Aside from Black Mountain and it's dumb dumbs. (Likely the F2 mutants) Most Super Mutants are just old fogies trying to live on peacefully.
@Doom- Well, I say that's the point of the Series, War destroys proper life. Genetic monsters arise from it. Monsters die of purging by 'normals' with the exception of the friendly ones. Humanity starts gearing towards Pre-War life.