You get a king's rock in BW1 by leveling a Pokemon by 99 levels. In BW2 when you visit Hilda/Bert's room the King's Rock is there which means they leveled a Pokemon by 99 levels. That means they must have a level 100 Pokemon!
Level 100 Pokemon= Strongest Trainer. Although my FEARon could probably take it.
Rocket Professor Al ~ R ~ Support Elesa! Rocket take over world!