Assassination Classroom

Nagisa Shiota is a male character whose long blue hair and slender build often lead to him being mistaken for a girl, a detail frequently highlighted for comedic effect. His mother, an emotionally manipulative figure, forces him to maintain this feminine appearance, as seen when she tries to cut his hair shorter in Episode 31, only to demand he keeps it long and even dresses him in girl's clothing at home. During the Okinawa Island arc (Season 1, Episodes 11-13), Nagisa is intentionally used in a cross-dressing disguise to infiltrate a group of delinquents as part of an assassination plan, further playing on his ambiguous gender presentation.

Irina Jelavić, nicknamed 'Professor Bitch' by the students, is a professional assassin who often uses her seductive appearance and methods as part of her assassination attempts. She is frequently depicted in revealing clothing and engages in flirtatious or suggestive behavior. In one instance, she gives a 'seduction class' to the students, teaching them about captivating targets and asking suggestive questions about intimacy. Koro-sensei frequently displays a perverted nature, such as his known 'fondness for porn magazines'. He is shown being easily distracted by or commenting on attractive women, and there's a reference to a 'rape joke' implying an unwanted sexual encounter with Ms. Bitch, though it was a one-time occurrence.

The character Irina Jelavić is almost exclusively referred to as 'Professor Bitch' or 'Bitch-sensei' by the students of Class 3-E throughout the entire series, from her introduction onwards. This name is used consistently and casually. Additionally, other milder curse words such as 'Hell' and 'Damn' are frequently used in character dialogue. An example of a 'curse cut short' occurs when Terasaka exclaims 'holy shi-' before being interrupted by Koro-sensei's response.

Adult characters, such as Irina Jelavić or government agents like Karasuma, are occasionally shown drinking alcohol, often in social or relaxed settings. For instance, Irina might be seen with a glass of wine after a failed assassination attempt. There are general mentions or implications of drug selling as a problematic societal issue within the broader context of the series, although specific scenes of drug use by the main student characters are absent.

The core plot involves a constant countdown to the Earth's potential destruction by Koro-sensei, creating an inherent sense of urgency and threat. Episodes featuring other professional assassins, such as the original Reaper or Shiro, introduce truly dangerous adversaries who pose lethal threats to both Koro-sensei and the students. For example, the 'Assassination Island' arc (Season 1, episodes 11-13) involves students falling ill from a fabricated virus and facing off against dangerous hitmen, forcing them into perilous situations. Koro-sensei's backstory as a human assassin, who committed violent acts and endured painful experiments, also presents a darker, more intense narrative thread, as revealed in Season 2.