User blog comment:VeiRetning/What UR Cards are worthy for Mirror Maiden?/@comment-25763904-20170412115037

I used my MM UR for old ranking cards like Niagara and a 450% light element buffer Melodica. Means I used them for cards I currently need the most or in the near future in order to be competitive in rankings.

I am planing to use a MM UR for a future event card which gives me a boost towards a good ranking success. This reduces the jewel I need for summon and I am a free player so my jewels are limited.