Gwendolyn Poole, better known as Gwenpool, originated as a visual concept in Marvel Comics during the 2015 "Gwen variants" cover series, first appearing on the variant cover of Deadpool's Secret Secret Wars #2, illustrated by Gurihiru. Her debut as a fully realized character occurred shortly thereafter in a backup story in Howard the Duck volume 6 #1 (November 2015), written by Christopher Hastings, followed by a lead feature in Gwenpool Special #1 (December 2015). These early appearances established her as a metafictional entity, leading to the launch of her solo series, The Unbelievable Gwenpool, in 2016.

Transported from the real world—where Marvel characters exist only as fiction—into the Marvel Universe, Gwendolyn Poole adopts the Gwenpool identity, blending aesthetic elements of Gwen Stacy and Deadpool. Lacking innate superpowers initially, she leverages her comprehensive knowledge of comic book events, tropes, and character histories to survive as a mercenary and later a superhero. Her medium awareness allows her to recognize narrative structures, such as plot armor and supporting character roles, which she exploits strategically, evolving over time into abilities that permit interaction with comic panels and gutters.

Throughout The Unbelievable Gwenpool (2016–2018), Gwen undergoes significant development, transitioning from a carefree, consequence-ignoring anti-hero to a more responsible figure confronting existential threats tied to her fictional status. The series culminates in her securing ongoing relevance within the Marvel canon. Subsequent appearances include joining the West Coast Avengers in 2018 and headlining the 2019 miniseries Gwenpool Strikes Back, where she acquires temporary enhancements while solidifying her identity as one of Marvel's first openly aromantic and asexual superheroes.