Mint (ALT72)

Mint (from the ALT72 universe) is another main character in Kill la Kill ALTERNATE, a fan-fiction story created by Ame Matoi in his early days of visual novel development. She only appears in the Crimson Year trilogy (along with Michael) as an antagonist in Crimson Year 1. 
The ALTERNATE project was cancelled in favor for Crimson. Ame Matoi has confirmed that the events of ALT are canon and happen in the Crimsonverse storyline, but they do not have any relevance to the main Crimsonverse story and the ALT story is only relevant to it's own universe.