Pessimistic Heroes, or just simply Pessimists are individuals who anticipate undesirable outcomes, or "the worst". These individuals often express doubt on anything positive and present a gloomy or wrathful attitude much of the time. Unlike their opposites, Optimists, Pessimists are relenting in defeat.

Prime examples include Squidward Tentacles, Shiki, Mandy, Raven, Zak, Sadness, and Yumi Yoshimura.

They should not be confused with Heroic Misanthropes, since pessimists do not have a true animosity with humans. They shouldn't be confused with Nihilistic either, as some pessimists might still believe that life has a purpose while nihilists embrace the belief that everything is meaningless. Pessimists have a chance to become purely good if they meet all the criteria and lack and/or shed their corrupting qualities.