Akira Takaoka

"Rule number one: we don't do "can't". Rule number two: We're a family and I'm the dad. Show a family where dad ain't in charge and I'll show you a family in crisis."

- Takaoka reveals his true nature

Akira Takaoka is a trained soldier, a former ally of Tadaomi Karasuma and an early antagonist of the series.

Appearance
Takaoka is a rather large man and claims that his love of food increased his waistline. He is also very muscular from years of intense training. He is first seen with a very friendly look on his face, but this drastically changed when he showed his true colors as a brutal drill sergeant. In his second appearance, he had clawed at his face to the point of leaving scars (reflecting the psychological scars inflicted by Nagisa Shiota) and has lost his large waistline. He also has black hair that is slicked back and black eyes and a big nose.

Personality
Takaoka appears to be a very kind and helpful man in his first appearance in Chapter 38. However the second half of Chapter 39 reveals that he is a sadistic drill instructor who abuses his strength and power through brute force and violence. He does not hesitate in beating up anyone, even the students (such as kneeing Maehara and slapping Kanzaki when they object to his training), just to show how powerful he is. The truth is he does not care about the students' welfare at all - he only cares about gaining fame from them killing Koro-sensei due to his teaching, as well as forcing Karasuma to acknowledge his methods and being able to boss him around. He hates losing to anyone, becoming deranged after losing to Nagisa.

After getting fired from losing to Nagisa, his insanity is amplified. He devised a plan to poison most of the students in Okinawa for his revenge. He began scratching his face due to being mocked by his colleague after he lost to Nagisa. After confronting the students again, he threatened everyone by telling them that he’ll blow up the antidote if Nagisa doesn't beg for forgiveness, (but once again he broke his promise by blowing up the antidote just to see Nagisa's despair). Once he lost to Nagisa for the second time, he was reduced to a vegetative state after seeing Nagisa’s smile.

He has an obsession of watching the suffering of his opponents and will sadistically beat/kill someone just to assert his control of others, furthering his dominance by forcing them to recognize him as their father figure. He also has a habit of raising his tongue whenever he has the upper hand.

History
When he was in the military, he was able to produce elite loyal troops in a short span of time by connecting with them as a tightly-knit family and standing as a violent father at the same time. It is assumed that Takaoka was never reported on due to the possible reprisals against any whistleblowers.

As a PE teacher
Takaoka first appeared as a new P.E. teacher for Class 3-E sent by Ministry of Defense as they were impatient of killing Koro-sensei. Once he appears, he greets the students and gives them food, drinks, and sweets as a sign of greeting them. He tells Class 3-E (minus Karma who skip classes again) that he'll be taking over the P.E. class from now on and self-proclaims himself to be their 'father'. Karasuma was then informed by the female bodyguard who accompanied him telling him that he's very dangerous. Sure enough, once Karasuma sees a second picture of him showing his 'previous family' his abuse, he begins to give Class 3-E a hell schedule with no time to study. He knees Maehara and slaps Kanzaki when they object to his training and forces Karasuma and Koro-sensei to see his hellish method of training. His goal is to gain fame and popularity after one of the students kills Koro-sensei due to his training and gets to boss Karasuma around. After attempting to punch Kurahashi who calls Karasuma for help, Karasuma steps in and demands him to stop abusing the students. Anticipating his actions, he decides to make a wager that if one of the students Karasuma selected stabbed or poke him with a knife, he'll leave the rest to Karasuma and leave the school. Otherwise, Karasuma has to allow him to follow up with his hellish training with no objections. However, he makes one of the students uses a real knife knowing he'll gain the upper hand as he knew his students had never held a real knife before.

Once Nagisa was selected, he belittles Karasuma for his decision as he observes Nagisa as the 'weakest' among the students. His actual plan was to avoid Nagisa's attacks and then beat him up so severely so that the students would have no choice but to obey him. Added, he also wants to see him in despair if he loses or forfeits the match. Unexpectedly, Nagisa casually walks towards him and subsequently pins him down with a knife in front of his throat. After regaining his composure, he openly refused to accept his loss and asks for a rematch. He finally snapped when Nagisa asked him to leave and was about to attack him before Karasuma elbows him in the face. To add insult to injury, Gakuhou Asano came and fires him for to his actions and being an ineffective instructor who only used brute force to gain control of the class.

Assassination Island Arc
After he left the school, he was mocked and teased by his upper-class superiors for losing to a junior high student. Unable to deal with the humiliation, he stole office funds and hired professional assassins to poison the students in Okinawa. Before the reveal, he spoke in the P.A. system that he has the antidote and wants Nagisa and Kayano to bring Koro-sensei to him. His identity was revealed when Karasuma suspects some of the bodyguards were part of his department and the sudden stolen funds that only a member of the department could stole it. He reveals to everyone that he plans to kill Koro-sensei by filling the anti-sensei bullets in the bathtub, tying up Kayano and burying both of them in the cement; letting Koro-sensei dissolve since he can’t expand without killing his own student. Threatening to destroy the antidote, he challenged Nagisa to a one on one fight to the death, blowing up the ladder to the helipad he was on so no one could aid Nagisa.

Takaoka then had Nagisa prostrate himself for humiliating him and being the source of his frequent nightmares (due to the facial expressions Nagisa had when 'assassinating' him back in school). After Nagisa had done so, Takaoka blew up the antidote anyway just so he could see Nagisa's frightened expression. As expected, Nagisa was filled with rage and picked up the combat knife, declaring his intention to kill him out of revenge. Despite Terasaka's attempt to cool down Nagisa by throwing his stun gun to him and some words, Nagisa appears to be goaded by Takaoka's words and continues to hold the combat knife while putting away the stun gun.

Both engage in a fight, though Takaoka easily overpowers Nagisa due to his build and experience, and the fact that he was prepared against Nagisa's attacks. Pausing halfway, he brandishes his own combat knife and tells Nagisa that once he wins, he will kill him and use his arms and legs as decoration. Unfortunately for him, Nagisa uses his stun gun after a well-feinted nekodamashi attack, immobilizing Takaoka and winning the fight. Following Terasaka's advice, Nagisa gave Takaoka a last jolt to his neck to knock him out, but not before giving him the smile Takaoka always saw in his nightmares, as a means of 'thanks'.

Takaoka never suspected that his hired assassins had double-crossed him by utilizing a weaker poison, due to him revealing to them that he never intended to give the antidote anyway. He was last seen being dragged away by the officers in restraints and was later interrogated for his actions.

Tadaomi Karasuma

 * Main article: Tadaomi Karasuma

Takaoka and Karasuma were in the same squad in the military but were in different sections. They both became instructors in the Air Force, but he has always been envious of Karasuma as the latter always had the best results. Him entering Class 3-E with a new training regime is a direct result of his envy, as he wanted to prove his worth, be responsible for the assassination, and have Karasuma become his underling. However, Karasuma does not share this view, and may not even know that Takaoka had despised him.

Nagisa Shiota

 * Main article: Nagisa Shiota

Takaoka sees Nagisa as a weakling, justifying his loss in their first fight as trickery. Unknown to Nagisa, his 'assassination' had caused deep emotional trauma to Takaoka, who spent every night onward having nightmares of his face. It is due to this hatred that caused him to think of revenge in the Assassination Island arc, as he felt that if he tortured and killed Nagisa, he would be absolved of his shame. Takaoka directly attributes his loss of respect in the Ministry of Defense to Nagisa's 'dirty' victory. However, because of his attitude itself, he was put into a constant state of shock after seeing Nagisa defeat and smile at him one last time.

Quotes

 * "To bring students under your thumbs, you have to give them just two things. Affection and Fear"
 * (To Class E Students) "What naughty children..., you came to see your respected instructor, and you come through the back entrance. Papa would never have instructed such children. Guess i have no choice. I'll give you guys supplementary lesson for your summer vacation!"
 * (His thoughts of Karasuma) "You, who were the best of the best in the unit... never paid attention to my strength, did you? That person of you has robbed me of any chance at a promotion. It doesn't matter if this destroys the majority of them. If I form those that remain into an elite corps, and they kill that octopus. As a hero who raised such heroes.. I'll be able to order you around!!"

Trivia

 * Ryoma Terasaka was called "Pseudo-Takaoka" during class 3-E training using code names, likely due to their similar build.
 * According to the Graduation Album, he was secretly released from custody and began worshiping Nagisa as a goddess. Eventually, after being convinced by Nagisa, he is currently considering becoming a monk.