Milieus has ash blond hair and blue-gray eyes. He wears the standard boys uniform of the school.
In the election for a new student council president, Milieus is present for the candidates' final speeches, and angrily reacts to Rico's presidential plans of forcing all students to clean the school on breaks, after school, and on non-school days.
In the school's 104th festival, Milieus, along with Daz, help operating the stage lights of a Snow White play.
When teachers get in the way of Eren trying to head to the Titans' building to retrieve his chee-burgs, Milieus, along with his classmates stand up for him and come between them. He later watches Ilse Langnar's broadcast of Eren and the others venturing into the principal's office, and cheers once Eren manages to retrieve a chee-burg.