Ectoplasm is a Pro Hero and member of the U.A. High School faculty who teaches mathematics. Ectoplasm is a tall, slender man with short hair and completely blank eyes tilted inwards. Due to losing his legs in the line of duty, he uses replacement prosthetics, and when in anything but his hero attire, he wears a pair of large glasses. In his hero costume, he wears a tan cloak that covers most of his body, the area over his torso, and the high collar resembling that of a double-breasted trench coat. Underneath this, he wears a skin-tight black bodysuit with a golden striped neck area and a matching black helmet that covers his entire head, a jaw-guard attached over his nose and around his jaw, and circular mufflers. He also wears baggy dark gray pants and a pair of thin, lightweight prosthetic legs. Ectoplasm is a steadfast and unrelenting hero, which has made him highly popular. As a teacher, he desires the best from his students and isn't afraid to push them; he openly warned Fumikage Tokoyami and Tsuyu Asui he would do his best to crush them during their final exams. He also told them he was looking for his students to shine under pressure.