po-devs/pokemon-online — pull request #1212 by Fuzzysqurl (2014-08-07 20:02:51+00:00)
Title: Remove Power Gem from Diancie until it gets confirmed

No site confirms where to get the move. It doesn't learn by leveling up, so it shouldn't be there. Probably going to be an event move or something, but until then it shouldn't be in there.