Mika works at the Battle Spirits shops where Hajime and other card battlers come to play. She is also a card battler herself, and used to be a member of her school's Battle Spirits club, under the advisor, Keisuke Saimon.
Mika is kind and seems to look out for Hajime and is like an older sister to him. She seems to care about all the kids, although, she acts much more harshly around Arata.
