Hollow

Once a brilliant scientist working with her husband on portal technology, Hollow was betrayed and tricked into working on a dangerous top-secret project. When this device exploded, it replaced her own heart with a portal to an infinite pocket dimension, and her husband vanished without a trace, presumed dead. Now almost emotionless, except for the desire for vengeance and the aching loss of her husband, Hollow has vowed to find or avenge her husband by tracking down the man who tricked them both and stopping him for good. To this end, she uses the infinite storage space in her heart and her new combat training to defeat corruption and evil wherever she finds it - especially if it provides a clue to the monster she is sworn to destroy.

This revenge is confined to school hours and after bedtime, however. Hollow may have lost most of her emotions, but she still knows that her two young daughters come first.