Since the unhidden maps were released, I got 3 of them in total so far and I collect a map 7 days a week. So the drop rate of the maps is quite low. And then you have another low chance to get the minion. That's why this one is ultra rare. Already Bluebird from Peiste skin maps costed 2 millions when it came out and it is still quite expensive on Ragnarok because it is so rare.