As one of the main characters of Soul Eater, Doctor Franken Stein is a manful and strange guy with short silvery grey hair and big round glasses, and there is a large screw going through his head, which makes him quite noticeable. And Dr. Stein often wears the black suit along with white lab coat.
In addition, Soul Eater Dr. Stein is a tall man and treats everything in the world as an experiment. So he is also a dangerous man. Probably, just because of this fact, there are so many cosplay girls and boys obsessed with him.