How do you evolve Pokemon on Pokemon mystery universe? - Answers

In PMU, you must defeat Registeel (found in the Ancient Relic dungeon). It consists of four main floors (five if you include finding the key) and at the end, you face four Bronzong and then Registeel. Once defeated, Registeel will give you a music box along with a variation of a few other items. Then, go back one square (where the poochyena are everywhere) and go up. Go up the rock steps to the cliff and continue upwards until you reach a small temple-like building. Enter it and at the top of the room, use the music box. You now have permanent access to PMU's equivalent of Luminous Spring. Enter the light to evolve. You won't get a confirmation box, so be sure you want to evolve before stepping in.