In the Mai-Otome manga, Mashiro is a boy who really resemble the real princess of the kingdom, Mashiro. The manga starts when the princess is declared dead and it's decided that a fake princess should be choose to avoid a war and administration problems, and Mashiro-boy is the chosen one.
Mashiro is initially a weak-willed adolescent boy, typically running away from problems and giving up. The manga's central plot is his development from a fake princess into a strong ruler. When he thinks to himself, he often pretends he is talking to his mother.
His real name has never been revealed.