Oldboy does not feature any identifiable LGBTQ+ characters or themes. The narrative centers on heterosexual relationships and the psychological torment of its protagonist, making the portrayal of LGBTQ+ elements not applicable to the film's content.

Oldboy does not feature any identifiable transsexual characters or themes. The narrative focuses on themes of revenge, imprisonment, and psychological torment, without exploring aspects of gender identity or transition.

The film Oldboy does not feature any female characters engaging in or winning direct physical combat against one or more male opponents. The primary combat sequences involve male characters.

The film "Oldboy" (2003) is an adaptation of a Japanese manga. All major characters in the film retain the same gender as their counterparts in the source material. No established characters from the manga were portrayed as a different gender in the movie.

The 2003 film "Oldboy" is an adaptation of a Japanese manga. While the characters' nationalities and ethnicities shift from Japanese in the source material to Korean in the film, this change falls within the same broader East Asian racial category, and thus does not meet the definition of a race swap.