The Ultimate LivingDex:Nuclear and Event Pokémon

[PhantomUnderYourDesk]

You can backup your original savefile externally on a hard- or flashdrive before making another so you're on the safe side if you're worried about loosing anything. I did so too just in case, everything remained intact though.

You could even make a second save file in which you collect all the Nuclear Pokemon only available at limited places/storytimes and then send them over to your LivingDex-file!~  Get yourself a Nucleon with good stats and you're through the required battles rather fast.