Charlotte Dunois
Being sent as a spy by her father, her appearance is that of an androgynous male with long blonde hair that is tied up in a ponytail. She has purple eyes and wears the same IS Academy uniform as that of Ichika. In episode 8, when she decided to re-introduced herself to the class as "Charlotte" Dunois, she wears the IS Academy female uniform with a skirt. Her IS Training uniform also changes to the female version with orange edges and has changed from a two piece to a one piece suit.

Cecilia Alcott
Cecilia Alcott (セシリア オルコット, Seshiria Orukotto) is a 1st year student at the IS Academy in Class One and the IS Representative Candidate of the United Kingdom. She is the 2nd heroine to be introduced to the Infinite Stratos series. She takes the appearance of a teenage British girl who has blue eyes, long blonde hair, and wears a blue headband. Her IS Academy uniform is slightly modified with a long skirt with black frills at the end of the skirt and sleeves. For her IS Practice and battles, she wears the blue version of their training uniform. Her IS in standby mode takes the form of ear accessories. She has a very good figure and looks that Ichika has compared to that of a model; she has admitted that she has worked as one in the past.

IS (Japanese: IS〈インフィニット・ストラトス〉 Hepburn: IS ) is a Japanese light novel series by Izuru Yumizuru with illustrations provided by Okiura and CHOCO. As of October 2013, 8 volumes have been published by Media Factory under their MF Bunko J label. From volume 8 onwards, the novels will be published by Overlap under their Overlap Bunko label. A manga adaptation by Kenji Akahoshi was serialized in the seinen manga magazine Monthly Comic Alive from May 2010 to July 2012 with five volumes published under their Alive Comics imprint. A 12-episode anime adaptation aired in Japan between January and March, 2011, and an OVA was released on December 7, 2011. The anime is licensed by Sentai Filmworks in North America, and they released the series on April 10, 2012. A second series aired from October 3, 2013 to December 19, 2013.