Twoearle

She's a white haired girl who came from another world that has been attacked by the "Ultimegil." Though, she has a high level of scientific and technical knowledge, she is very much a klutz where she would often do things or say things carelessly that gets her to be on the receiving end of Aika's ire. She likes Souji very much that she would often flirt around him in a very ridiculous manner, much to Aika's chagrin.

She later on enrolled to Souji's school, where she is also his classmate and adopted the same last name as Souji, Mitsuka, under the pretense of being his cousin.

(Source: ANN)