User blog comment:VeiRetning/What UR Cards are worthy for Mirror Maiden?/@comment-26039274-20170412144218

With the current game setup, it is best to use a MM on card/s that can help you earn points in IEH (MH, Salvo, Team Unleasher, Super Buffers), which would thereby result in higher ranking to get good RR cards. And on cards that can help you survive AEH and AEH+ for materials gathering, especially on events that requires you to do said EH modes in order to get the event card.