Napstablook was brought to UMH by his cousins, Mettaton and Mad Dummy. He'd been acting strangely for some time before they admitted him, sometimes even seeming to take on new personas.
Napstablook looks like his normal self, headphones and all. However, his personas can alter his appearance. (More info on this later)
Napsta's personality is rather child-like. He tends to stay by himself and create things. His other personas can alter this. (More info later)