Kieron Michael Gillen is a British comic book writer and former video game and music journalist. In comics, Gillen is known for his creator-owned series such as Once & Future (2019–2022), Die (2018–2021), Phonogram (2006–2016), and The Wicked + The Divine (2014–2019), the latter two co-created with artist Jamie McKelvie and published by Image. He is also known for numerous Marvel Comics projects, such as Journey into Mystery, Uncanny X-Men, and Young Avengers in the early 2010s and Star Wars comics in the mid-to-late 2010s including Darth Vader, Star Wars, and co-creation of the character Doctor Aphra who starred in her own ongoing spin-off comic series Star Wars: Doctor Aphra of which Gillen wrote the first 19 issues. He returned to the X-Men in the 2020s with multiple series during the Krakoan Age for the Destiny of X, Sins of Sinister and Fall of X storylines.

Die is a horror/fantasy comic book about role-playing games, influenced by the portal fantasy and LitRPG literary genres, written by Kieron Gillen and illustrated by Stephanie Hans. The series focuses on a group of British adults who are drawn back to an icosahedron-shaped world they originally visited as teenagers; the group left behind a friend upon their original escape and never discussed the experience. It was published by Image Comics and ran for twenty issues across four five-issue arcs, beginning in December 2018 and ending in September 2021.