>NIDORINO's poisonous horns and violent disposition serve to intimidate CLEFAIRY and scare them out of their caves.
>Though only one Moon Stone is required for evolution, NIDOKING tend to horde many of them in their dens as a sign of status over their rivals.
>While less aggressive than their male counterparts, NIDORINA excel in locating and digging up CLEFAIRY's secret troves of Moon Stones.
>NIDOQUEEN's exposure to lunar radiation mutated it into a much more powerful form. It also enhanced it's motherly instinct.
>Constant battles with raiding NIDORINO caused CLEFAIRY to develop a magical shield to guard it from poison.
>CLEFABLE's acute hearing warns it in advance of trespassers in it's cave, and allows it to make a quick escape with it's precious Moon Stones.
I was trying to come up with some reason why the Nidos are randomly associated with Moon Stones, ended up with this. Could use some work but it has the general ideas I wanted, let me know what you think