In Pokemon X and Y, I checked my Yveltal and it has 3 perfect IVs. A friend of mine told me that having 3 IVs on average in Pokemon X/Y for Yvetal and Xerneas is normal. Can anyone confirm this?
I'm trying to narrow down the exact generation where this became a mechanic, but at least as of Generation VI, all Pokemon encountered in the wild that are unable to breed (Legendaries, baby Pokemon, etc.) are guaranteed 3 "perfect" (31) IVs.