When the Third Wheel Strikes Back

 When The Third Wheel Strikes Back  (서브 남주가 파업하면 생기는 일) is a novel written by the author 숙임 (Sook-im) that first began serializing on Munpia on May 11th of 2020. (Promotional trailer.)

The second and third cover illustrations were made by 러기럭.

Synopsis
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One day, Jung Yeseo wakes up to find himself in the world of the popular hit romantic fantasy novel by the name of "I Quit My Job and Ended Up as a Noble Young Lady in Another World" in the body of Jesse Venetiaan, a prince of the Holy Kingdom and the second male lead of the novel, who had been sent to the Riester Empire as a diplomatic hostage.

In order to prevent his original fate of dying on the battlefield after shielding the Imperial Crown Prince and male lead of the story—Cédric Riester—Jung Yeseo, now Jesse, decides that not getting involved with MCs (the Imperial Crown Prince, and female lead of the story, Christelle de Sarnez) would be the best course of action to take in order to increase his chances of survival.

Trivia

 * In 2020, the novel won the Rookie of the Year Award at the 6th Munpia Web Novel Contest.
 * On December 30th of 2021, it also won the Grand Prize in the Fantasy eBook category during the Ridibooks Web Novel Awards.
 * A blog article was written about TWSB's popularity with Gen Z, with the points and reasons for its popularity being:
 * The unique takes on clichés,
 * The refreshing point of views that come with having two transmigrators (with only one party being aware of the other being the same predicament),
 * The MC's nice personality,
 * and the presence of cute divine beasts and desserts!


 * The official English title was revealed by the author on April 5th, 2021, in the end notes of Chapter 234: Curtain Call (6), as a reference to the movie: "Star Wars: Episode V – The Empire Strikes Back."
 * Before this revelation, TWSB was previously translated as "What Happens When the Second Male Lead Goes on a Strike" or "What Happens When the Second Male Lead Powers Up." Please refrain from using these titles, as they are unofficial and we should respect the author's choice of English title.

Pop culture references

 * The official suggested English title—"When the Third Wheel Strikes Back"—is a reference to the movie: "Star Wars: Episode V – The Empire Strikes Back."
 * Upon finding out that Cédric Riester was a "magic swordsman" and not a "sword master" like his sister told him about, Jesse makes a reference to the X-Men and wonders if the imperial prince is some sort of mutant.