Sara Gallagher

A Meister Otome, Column #1 of the Five Columns, the Galactic Aquamarine (銀河の藍玉 Ginga no Rangyoku). She first appears in ep. 24, bringing "presents" to Aries from Zipang after a mission in the Eastern Territories. Her Element is a giant boomerang, and she has the ability to turn herself invisible. She also frequently scolds Haruka for her mispronunciation of words and was Mai's room attendant when she was at school.
-From Wikipedia