Mikasa is Eren's childhood friend, along with Armin. Mikasa shares an unbreakable bond with Eren following events in their past, and rushes to protect him whenever he is in danger. Mikasa possesses impressive fighting skill and strength even as a child. As a teen, Mikasa is considered a genius among all the army trainees and is incredibly skilled at combat and agility. She constantly worries for Eren's well-being and lives to protect him.

Formerly a prodigy child actress, Kana Arima lost most of her footing in the entertainment industry due to the poor reputation she garnered for herself on set during her grade school years. Though her attitude has greatly reformed by the present day, her image as merely a washed-up child actor continues to hamper her efforts.