Ken Sudō

Ken Sudō is a student of class 1-D and a member of the Basketball Club.

Due his poor academic ability, he is referred to as one of the "3 Idiots of D-Class". Regardless of this, his athletic ability is without a doubt one of the best among the school.

Appearance
Aside from his dyed red hair and an inappropriate hairstyle, he possesses an intimidating look, which makes it harder for others to get closer to him.

His height of 183 cm combined with his sturdy, muscular physique easily leaves an impression of a competent athlete on others. His clothing style also suggests his wild and aggressive personality, as he lets loose of his upper shirt's buttons.

Personality
Ken puts very little efforts in his studies, which grants him the nickname, alongside two of his classmate, who share his lack of academic abilities, "3 Idiots of D-Class". He is always seen to sleep in class, and also once refused to join Suzune Horikita's study group for the sakes of his grade.

He is known for having hot headed temper as he is quick to get angry when people do what he deems pointless as well as when someone insults him being ready for a fight, showing how easily provoked he can be. When others try to help him by stopping him, he exclaims that he doesn't need their help and shows anger at the person who taunted him walks away. Despite his eagerness for a fight, he is shown to get scared when he is overpowered as shown in his confrontation with Kakeru Ryūen.

Ken enjoys basketball and wants to go pro, he is very attached to this dream as he was worried when Suzune mentioned he might not able to play if he were to expelled from the school.

During the cruise in Episode 8, he quickly asks Ayanokōji over Suzune Horikita's first name and after being told he got excited. He started blushing while saying her name repeatedly, meaning he might have developed romantic feelings for her, in spite of their previous hostile interactions.

Plot
He is first seen criticizing Yōsuke Hirata for proposing the class introduce themselves angrily calling it childish. After he and the class are told about points, Sudō is one of the few most excited and for the next month he uses his for trivial things while often seen hanging out with Kanji Ike and Haruki Yamauchi. He nearly got into a fight with students of Class C but they instead leave while mocking him.

Days later, he is approached by Ayanokōji to join Suzune's study group but angrily refuses though Suzune herself meets him and makes him think about his athletic career and how it would be at stake if he were to be expelled which persuaded him to go study. However, he leaves after Suzune insults them and is joined by Ike and Yamauchi. He is next seen getting into a confrontation with Kakeru Ryūen while grabbed by two students of Class C, he is intimidated by Ryūen. He breaks free and tries to attack him but its broken up by Honami Ichinose and Class C walks off as Sudō tries to stop them but Ayanokōji arrives and stops him. In a huff, he refuses to rejoin the study group and goes to basketball practice where his thoughts are filled with doubt over a possible failure.

Afterwards, he is given old test scores by Kikyō Kushida and is relieved to hear that there was chance to pass the test.

While the whole class passes the test, Sudō is the only one who didn't get a passing grade being one point away. He is told by Chabashira he will be expelled immediately, much to his dismay. Unbeknownst to him, Ayanokōji and Suzune came to his aid by sacrificing 50,000 points so he wouldn't be expelled. Later on, a celebratory party is thrown at Ayanokōji's room where Sudō and some other students attend with him being relieved that he didn't failed. When Kikyō talks to Ayanokōji and hints that he helped Sudō out, the latter and the others stop their activities and looked to see if this was true but he casts the credit to Suzune. A startled Suzune was barely able to explain to a curious Sudō that she did it for her own benefit.

Sometime later, Sudō gets into an altercation with Daichi Ishizaki and other students of Class C in the stairwell. He overpowers them which causes them to launch a complaint against which could possibly get him expelled. As a consequence his class does not receive points, he is berated for his confrontation by his class but he insists his innocence. When Kushida forms a group to prove his innocence, they all meet in Ayanokōji's room after the search for witnesses proves fruitless, much to Sudō's annoyance.

At his hearing, he is accompanied by Ayanokōji and Suzune as well as Sae Chabashira. Things don't go his way at first until Suzune (with Ayanokōji's help) speaks and delivers a speech which imply the fight was a set-up. She proves it by asking all three boys of Class C why they were all present at the stairwell. Sudō is shocked to hear there was someone who witnessed everything his classmate Airi Sakura. He is further shocked when she provides proof of her presence with a picture of herself and a glimpse of the fight in the background. This is considered minor as it didn't prove who started it just that she was there but Kazuma Sakagami proposes a compromise. He suggest a three week suspension for Sudō while a two week sentence for Class C but Suzune doesn't accept it. She voices her opinion of Sudō where she criticizes him, which angered him at first but she stated he was not at fault for this incident to his shock. Sudō watched as Suzune demanded the dismissal of the accusations towards Sudō as he is amazed by her speech. He gets into an argument with Class C about this proclaiming his innocence but the argument is stopped by Manabu Horikita who says he will give his verdict the next day.

A day later, Class C withdrew their complaint against Sudō, much to his joy. At the courtyard, he found and informed Kiyotaka of this news (not knowing he aided in this act). Kiyotaka congratulated him on this and when the relieved Sudō wondered Suzune did something to help him, Kiyotaka again gave her the credit. After the brief celebration, Sudō called Suzune amazing for her actions before he left for practice as Kiyotaka looked on.

On summer break, the 3 Idiots of D-Class, Hideo Sotomura and Kiyotaka Ayanokōji make a plan to peep on the girls by inviting them to the pool. After a few circumstances, in which Ike is trapped in the women's locker room and the long line of people from other classes form to enter the room, Sudō is forced to distract them. Sudō is met with a problem when the Student Council President arrives demanding he move out of the way. Luckily, Sotomura signaled Kiyotaka and he had Suzune distract everyone long enough for Ike to escape unnoticed by anyone. While this happened, Suzune stole the memory cards for the peeping incident. Though the plan failed, he enjoyed his time at pool with his friends and classmates.

During the cruise, he quickly asks Ayanokōji over Suzune's first name and after being told he got excited. He started blushing while saying her name repeatedly before he leaves with his group. While going to get lunch at a fancy area on the cruise, they are insulted by Yahiko Totsuka who berates them as trash which causes Sudō to grab him but it is broken up by Kōhei Katsuragi.

Trivia

 * In the light novel, Ken Sudō and Kiyotaka Ayanokōji are actually friends.
 * The anime has not fully developed their friendship yet.
 * As Class D is for people with defective traits, Sudō has a hot headed temper and low intelligence.
 * He has been at risk of expulsion twice in the series for two separate reasons that deal with a personality flaw of his. In both those times, he was defended in some way by Kiyotaka Ayanokōji and Suzune Horikita.
 * In Episode 3, his inability to study causes him to be the only student to fail but he is saved by Kiyotaka and Suzune sacrificing their points which caused the teacher to change the decision.
 * In Episode 5, his quick temper and eagerness to fight causes him to be accused of attacking and injuring three students of Class C. At his hearing, Kiyotaka and Suzune come to defend him to prove his innocence in the terrible incident. In Episode 6, he was cleared of the incident due to Class C withdrew their complaint against him after they realized they were recorded by a surveillance camera.