Character:

The Servant of Shinji, first seen scouting around Homurabara Gakuen. Rider is silent, sultry, and vigilant, never hesitating to shield her Master from harm. With Shinji incapable of lending Mana to her, she is forced to seek alternative means to augment her abilities. To compensate for her weakness, Rider employs covert battle tactics and takes full advantage of territory around her. Her weapon of choice is a pair of long iron nails fastened to opposite ends of a single chain, which she effectively thrusts from distances. She was Medusa in past life.

Source from Wikipeida