Takeshi Kono is the protagonist of Mo-Retsu! Boing Sensei.==
Takeshi Kono is a 26 year old substitute teacher with an obsession with pornography. He would masturbate to most porn videos he would watch and review them. He claims he can only eat ramen because of how difficult rice can be to eat. He used to be a very studious student until Aya secretly sent him his first porn video. From then on he became obsessed with porn to the point he developed a mindset where everything can be a porn setting, and treating every adult video seriously.
Throughout the series, Kono gets involved in a sexual relationship with many of the teachers at school, though some of the relationships are more than just sexual.
Ms. Motokura was the first teacher Kono meets at the school where Kono immediately mistook Miki for Kozue. This led to Kono raping Miki before finding out that she really is not Kozue (due to a watermelon seed he mistook for Kozue's breast mole). While Miki was not too pleased with the encounter, she eventually warms up to Kono and even revealed some feelings for him.
Despite Kono's erotic behavior, his feelings for Miki had led him to become more protective of her, as evident when he didn't feel comfortable with Miki modeling her revealing maid outfit at a Halloween event in school.
Takeshi's favorite porn star, Kozue was eventually revealed to be Miki's sister. She asks Kono not to tell Miki anything regarding her porn career.
While the fastest rising porn star, Kozue had moments during filming where she just seemed out of it. Veteran porn star turned director Asuza Suzumiya eventually revealed that Kono's presence is what drives Kozue to perform well.
One of Kono's students, Maki was present when Kono accidentally revealed that he is obsessed with porn and how he masturbates to it every day. Maki is straightforward in pointing out how Kono is obsessed with porn.
While the two never had a sexual encounter, Kono revealed that he liked Maki. He didn't reveal, however, how deep these feelings were. He is also protective of Maki in a teacher-student level, promising to keep quiet about Maki's job.
While A teases him often and Kono seems to shows annoyance by her wild, disrespectful behavior, the two do show sexual desires for one another. Anna even initiates sexual acts with him at some points. Their relationship is more friendly due to common interest in Japanese history and culture.
Takeshi assists Miss Shirakawa with PE and the gymnastic club. She tried to make him get over his leotard fetish by having sex with him but that didn't work. Now she becomes involved with his other gym related fetishes like bloomers and swimsuits. Shirakawa has shown signs of wanting to be his wife.
Miss Morioka mistook Takeshi as a virgin when she first met him, and grew a form of hatred toward him. However, Takeshi's strong interest in trying different kinds of sex and Morioka's interest in virgins causes her to have an interest in him. Their relationship is mostly comedic with Takeshi thinking she's too old.
Takeshi and Kazuha Higuchi both share an interest in erotic novels. He even likes reading one of her own. This has caused Ms Higuchi to enter a master/servant roleplay with him, with her as the submissive servant.
After realizing that he is tone deaf, Kono went to Ms Domyoji, the music teacher, to cure him. He sees her pretending that her recorder is a penis and promised to keep what he saw a secret if she practice falettio on him.
As Vice Principle, Egawa serves as Takeshi's boss. She has stated that he reminds her of her late husband.
Kono loved watching her movies when he was in college and still watches them. Kono's passion during sex with Kozue gave her the desire to return staring in adult films again.