Korosensei J-Stars VS
Gender Male
Species Genetically-engineered Organism
Hometown Tokyo, Japan
Class Teacher
Debut Assassination Time
Current Status(es) Alive
Affiliation(s) Class 3-E
Alias(es) Octopus,
God of Death,
Stupid Chicken Pervert Octopus
Relation(s) Itona Horibe ("brother")


Korosensei's trademark laugh

Korosensei (Japanese: 殺せんせー Koro-sensē) is the main antihero of the anime and manga series Assassination Classroom. Formerly a human hitman named God of Death, Korosensei is a genetically-engineered creature with various different abilities that make him near-invincible. He serves as the main teacher of Class 3-E of Kunugigaoka Junior High School, and also as their assassination target. Korosensei is primarily portrayed by Jun Fukuyama in the Japanese anime and Sonny Strait in its English dub, though was also portrayed by Tomokazu Seki for his appearance in the fighting game J-Stars Victory VS.

Physical AppearanceEdit

Korosensei stands at 280cm tall (9'2"), and as such stands well above any of the Class 3-E students, Tadaomi Karasuma and Irina Jelavić. He has a large bulbous head with two small eyes and a large smile that rarely wavers. He has yellow skin, and eight tentacles; two of which have feelers on the end and are used as arms, while the rest as "feet". He wears a black academic dress with a square graduation cap with yellow tassel. Under his chin, he wears a black tie with a crescent shape printed on it.

Notably, the colour of Korosensei's face changes with his emotion. Among many, these faces include:

Korosensei faces

Korosensei's faces

  • Green = Happy
  • Yellow with Green Stripes = Mockery
  • Pink = Sleepy
  • Purple = Shock/Panic
  • Blue = Sadness
  • Red = Anger
  • Black = Extreme Anger
  • White = Serious
  • Orange with a Red Circle = Correct Answer
  • Purple with a Dark Purple X = Incorrect Answer

When in public, Korosensei changes his face to be a peach colour, and adds an artificial nose to his face. Atop his head he wears fake hair and wears a blue baseball cap to disguise him as a human.

When in extreme danger, Korosensei can shrink his head down to the size of roughly a large goldfish, and will use the energy of his body to create an impenetrable barrier. He calls this his "Perfect Defense Form".


Korosensei is extremely intelligent, to the point where he could teach every subject alone. His intelligence also allows him to predict the outcomes of events, and as such he is usually seen a few steps ahead of everyone else. Aside from his intelligence, Korosensei acts somewhat of a child himself, with a deep, irresistible love of sweets. He also harbours a perverted side, which he shares with his student Taiga Okajima; and is shown to be unable to resist the large breasts of women. He is also extremely kind and somewhat sillhy, though this can almost instantaneously switch to being serious.


While Korosensei harbours a large amount of power, such as the ability to fly or to travel at Mach 10 speed, Korosensei has a long list of weaknesses, which he tries his best to keep hidden from his students and others who target him. Nagisa Shiota keeps track of all his known weaknesses in a notebook:

  1. When he tries to act cool, his weaknesses show
  2. He is surprisingly quick to panic
  3. He is petty
  4. His punches are weak
  5. Boobs
  6. He is humble and subservient to his superiors
  7. He has no patience for wire puzzles
  8. He gets motion sickness
  9. He can't sleep on a pillow other than his own
  10. He worries about appearances
  11. He can't handle hot food
  12. Getting wet
  13. Juicy gossip
  14. Hackneyed plot developments make him cry
  15. He gets taken in by rumors
  16. Time right after molting
  17. Time right after regeneration
  18. His body goes rigid when bathed in a special beam of light
  19. When he returns to normal after a serious situation, he gets embarrassed
  20. He can only draw simple pictures
  21. Heat fatigue
  22. He's strict about poolside manner
  23. He can't swim
  24. He likes to gossip
  25. He is weak against the occult
  26. If he can't gather people he feels worthless
  27. Tone-deafness
  28. He sucks at hiding
  29. Gets carried away by official positions
  30. Heart
  31. Not related but acts like a doting parent
  32. Gets insurance to avoid getting hurt
  33. He doesn't really know what "your own football" means
  34. He sucks at reporting
  35. He suffers from road rage
  36. Restructuring
  37. Grabbing all his tentacles at once makes him unable to move


Fighting ComplexEdit

Korosensei, alongside Itona Horibe, is featured as a playable character in the game Fighting Complex. Korosensei's abilities have been extremely toned down for his appearance in Fighting Complex, though is still extremely fast in both moving and attacking.

Assassination Classroom: Chaos TimeEdit



  • Korosensei's name was given to him by Kaede Kayano. It is a combination of the words 殺せない (korosenai; unkillable) and 先生 (sensei; teacher).
AssClass-Chaos Time
KorosenseiTadaomi KarasumaIrina JelavićLovro BrofskiHinano KurahashiHinata OkanoHiroto MaeharaItona HoribeKaede KayanoKarma AkabaneKirara HazamaKōki MimuraKōtarō TakebayashiManami OkudaMasayoshi KimuraMegu KataokaNagisa ShiotaRinka HayamiRio NakamuraRitsuRyōma TerasakaRyūnosuke ChibaSumire HaraSōsuke SugayaTaiga OkajimaTaisei YoshidaTakuya MuramatsuTomohito SuginoTōka YadaYukiko KanzakiYuzuki FuwaYūma Isogai
Kunugigaoka Junior High

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