Mikki is a very complex character, with very little info I did my best to come up with a backstory. For more info go here https://scratch.mit.edu/projects/102423551/ She would come in later in the series.
Backstory
My past is unclear. My future is unclear. I only have myself, the mysterious voices in my head, and my brother. It's hard to live being a shadow night. The things I have to hide from my brother are unbearable. I come back at 12 o'clock with brother asleep on the couch, I just wonder what would happen if he found out. I know one day we will become enemies. Hopefully it won't cross that line. Sometimes he heres me through the walls in my shadow knight form, sometimes he can see little glimses of me, it's scary knowing that you have someone that you can taint without knowing it. Well I hope everything goes well