Why Dark Mercia Sucks
I actually enjoy playing her so give her a try
To unlock her, you must get 100 stars after beating the last mission of the campaign. After that, a mission will be unlocked and once that mission is finished, Dark Mercia is unlocked.
0:00 Introduction
0:25 Why she is weak
1:51 How to play DM
4:08 How to play against DM
5:25 Possible Improvements