Power of the Plates

After attuning wiith the Iron Plate, a strange phenomena occurred. While everyone was attempting to get the Icicle Plate under control as it spews out subzero Ice-Type energy My hands became heavy, and gained a metallic sheen! It was as if they were steel themselves... Was that in relation to the Plates being in close proximity, or was something else causing a reaction?
 
Maybe the Plates aren't just relics, but pieces of the same puzzle.