Doris Ruridou 瑠璃堂どりす

As the third and youngest daughter of the rich family that owns Rasen Advertising, her usual rich way of living gets spoiled by her being forced to go to a all girls boarding-school. Doris is also a Panzer and can transform at will into the Drill Princess. The name comes from her using a drill as both a weapon and a fashionable hat, though no one else seems to think that her Panzer-suit is fashionable.