Mitsuki Sanada

Mitsuki is the most admired girl in Kazuki's school; young men constantly send her gifts and cards, and Kazuki is nearly lynched for speaking to her. She lures Kazuki to her house for her father's experiments, but is sent to the parallel world along with him. Mitsuki is also an exceptional robot pilot, and joins the EDF to end the war, hoping research to send her home can begin afterwards. Unfortunately, Mitsuki is hotheaded and easily manipulated, and is captured by the Rara Army towards the end of the series and coerced into piloting the complete version of Himiko. She clearly has an attraction to Kazuki, but covers it up by treating him abrasively.

When Kazuki is lost behind enemy lines, Mitsuki is affected most of all. (Source: Wikipedia)