Nozomu Itoshiki, nicknamed “Zetsubou-sensei” or “Mr. Despair,” is a high school teacher defined by relentless pessimism and theatrical suicidal gestures. His name, written horizontally in kanji as “zetsubou” (despair), mirrors his bleak perspective. He dresses in a traditional kimono and hakama, with sleek black hair framing green eyes accentuated by round glasses.

His fatalism stems from accidentally joining a “Negative Club” in high school, which cemented his habit of viewing existence as inherently futile. Though he frequently stages elaborate suicide attempts—using nooses, poisons, or other darkly humorous methods—he survives through absurd coincidences, gaining the unintended ability to commune with the dead. These acts lack sincerity, as he often berates others for “threatening” his life despite his own recklessness.

As an educator, he oversees a class of peculiar students who routinely misinterpret his nihilistic ramblings as profound wisdom, sparking misguided romantic infatuations. His lessons involve lashing out at societal conventions and dissecting life’s pointlessness, often spiraling into impassioned tirades punctuated by his despairing catchphrase. Despite his aloof exterior, he sporadically reveals hidden care for his students’ struggles.

The Itoshiki family relentlessly pressures him to wed, resisting their demands while navigating the clan’s name-based puns symbolizing severance and demise. The narrative concludes with him marrying his entire class—living, deceased, and male alike—aligning with the story’s absurdist humor.

Across adaptations, including the OVA *Zan Sayonara Zetsubō Sensei Bangai-chi*, he remains a perpetually harried cynic enduring surreal misfortunes. His design and existential anguish draw direct inspiration from Osamu Dazai’s *No Longer Human*, echoing themes of alienation and despair.