There are lots of anime series that initially struggle, only to eventually find their footing in a big way, but Assassination Classroom is the exception that instantly engaging. The addictive premise tasks a number of juvenile delinquent students with the execution of a powerful alien, Koro-sensei, who also happens to be their helpful teacher.

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It’s a fulfilling and surprising anime that doesn’t drag itself out, which can be a serious problem within the shonen genre. Assassination Classroom is fascinated with Koro-sensei’s unusual anatomy and the character’s weaknesses and strengths become integral to the series. Many powerful abilities aid Koro-sensei in survival, but there are also plenty that are more frivolous or barely get put to use.

10 He Can Create Highly Capable After-Image Replicants

Anime Assassination Classroom Koro-Sensi After Image Studying

One of Koro-sensei's most advertised assets is how fast he is and that he can move around the world at velocities up to Mach 20 like he’s some kind of superhero. Koro-sensei's intense speed is also shown to have another purpose, which is used more for visual gags than an advantage in battle.

Koro-sensei's speed can produce many after-image versions of himself, but rather than merely act as illusions, they can also carry out rudimentary tasks. It doesn't just confuse the opponent, but is a brilliant way to maximize limited time.

9 Koro-sensei's Mucus Is A Miracle Product Of Resistance

Anime Assassination Classroom Koro-sensei Mucus Crying

Assassination Classroom begins with Koro-sensei being an absolute mystery to both Class 3-E and the audience, but he slowly reveals more about himself and his unusual quirks and abilities. An early ability that Koro-sensei demonstrates, much to Class 3-E's chagrin, is a slimy mucus that his body expels.

This mucus is very helpful for Koro-sensei since it doesn't just protect him, but it also waterproofs him and helps him stick to surfaces. Koro-sensei's "power mucus" becomes less integral as the anime move on and he shows off grander abilities.

8 Koro-sensei's Absolute Defense Mechanism Is The Ultimate Final Strategy

Anime Assassination Classroom Koro-Sensei Absoute Defense Ball

The destruction of Koro-sensei is fundamental to Assassination Classroom's story and there are several occasions where just when it seems like Class 3-E has outsmarted Koro-sensei, only for him to turn out a new trick. His Absolute Defense maneuver isn't used until the class's Okinawa trip, and even then, it's only used in extreme scenarios.

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Koro-sensei shrinks down to a tiny ball that's protected by a durable shell. It takes 24 hours for Koro-sensei to regain his strength and return to normal, and he's immobile during this time.

7 His Beyond Durable Digestive Tract & Teeth

Anime Assassination Classroom Koro-Sensei Eats

Class 3-E is forced to think outside of the box with their attempts to defeat Koro-sensei, which often see them turning to execution methods beyond standard weapons. The class briefly plays with the idea of poisoning him or otherwise tainting his food in some way being the key to Koro-sensei's death.

It's revealed that he can practically digest anything or dispose of it in a molted manner. His teeth are also incredibly durable, not that it's helped him often. Koro-sensei is still subject to occasional side effects from what he ingests, but his body's unusual metabolism isn't explored very often in the anime.

6 He's A Brilliant Chemist

Anime Assassination Classroom Koro-Sensei Poisons

Part of the fun of Assassination Classroom is that Koro-sensei doubles as both Class 3-E's educator as well as the Earth's tormentor. It's logical that Koro-sensei is smart due to how he's become a teacher, but he pushes how he has an advanced photographic memory that retains entire textbooks.

In addition to this basic knowledge, Koro-sensei refines special chemistry skills after the experiments that Manami Okuda performs. Koro-sensei is able to develop a formula that allows him to liquefy, yet his proficiency in this field is never put to further use as the series continues.

5 Koro-sensei Has Turned To Pacifism, But He’s The Ultimate Killing Machine

Anime Assassination Classroom Koro-Sensei Human Form Rifle Assassination

Koro-sensei becomes a beloved character throughout Assassination Classroom and he helps every student in Class 3-E mature in some crucial way. The anime is at its best when it highlights the altruistic nature of Koro-sensei, which hits harder since he's introduced as a destructive alien that nearly takes out the entire moon.

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Koro-sensei used to be the world's best assassin, known as the Reaper. Despite this history, Koro-sensei doesn't like to kill any longer and one wouldn't know he possesses these skills, even if he can flawlessly avoid assassination attempts as a result.

4 Koro-sensei Wields Unbelievable Surgery Skills

Anime Assassination Classroom Koro-sensei Intense Studying

Defeat and loss can be extremely powerful motivators and Koro-sensei is greatly humbled after he loses Aguri from an injury that proves to be fatal and his abilities aren't enough to save this life. Koro-sensei takes it upon himself to study and practice methods of surgery to prevent such a tragedy from happening again.

Koro-sensei puts this ability to use when he removes a brain tumor from Azusa without complication and helps heal Kayano, but it's still a rare ability for him to put into practice.

3 Molting Is Just A Monthly Procedure For Koro-sensei

Anime Assassination Classroom Koro-Sensei Molted Skin

Assassination Classroom’s Koro-sensei is a major enigma, but Class 3-E slowly learns that many of his customs and habits mirror those of animals. For instance, Koro-sensei experiences a stage of molting where he sheds his skin to recharge.

The molted skin can be used for exceptionally durable cover, which is helpful since Koro-sensei's skills are slightly reduced during this period of renewal. It's a regular way for Koro-sensei to recharge, but once a month is still a lot more uncommon than most of Koro-sensei's basic abilities.

2 He Has A Mastery Over Technology

Anime Assassination Classroom Koro-Sensei Upgrades Ritsu AI

Koro-sensei exhibits a general worldly knowledge in Assassination Classroom, but when Ritsu is in need of help he jumps on the occasion to not just upgrade her, but drastically improve upon her hardware. Koro-sensei just tinkers around with Ritsu for a single day, but he performs nearly 1,000 modifications and upgrades in that time, including the addition of sentience and basic free will to Ritsu's AI.

With this degree of tech-savvy, Koro-sensei could build a defense system to keep him safe or create unbelievable weapons for his class, but it's instead a passing fancy for Koro-sensei.

1 Koro-sensei's Tentacles Can Unleash Laser Blasts Of Energy

Anime Assassination Classroom Koro-Sensei Angry Energy Attack

Koro-sensei is equipped with many elaborate defense mechanisms to maintain his survival, but even beyond these fancy tricks, his basic tentacles, speed, and regenerative abilities are more than enough to keep the extraterrestrial alive.

An added ability that Koro-sensei develops as a result of his Absolute Defense maneuver is that he can channel energy into his tentacles and unleash it as a laser. It's a skill that feels unnecessary considering how powerful his tentacles already are and it's not used as often as it could be considering its strength.

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