Matt Dinneman’s Dungeon Crawler Carl books are based on the premise that an extraterrestrial consortium called the Syndicate has attacked the Earth to mine it for rare minerals or elements and turned it into an 18-floor dungeon. At the start of Dungeon Crawler Carl, the first novel of the series, Carl is outdoors at 2:00 am on a winter night trying to lure Princess Donut back into the house, when a sudden attack, hereafter known as the Transformation or the Collapse, flattens all the buildings on Earth, killing everyone indoors. The remaining few million people are given a choice by the Borant Corporation—a Syndicate member entity to whom Earth has been leased for mining—to either stay on the surface and fend for themselves, or enter the dungeon.

In the dungeon, built like a funnel, the survivors or crawlers must descend through increasingly dangerous floors and fight occupying alien factions while the galaxy watches for entertainment. As Carl takes the option to enter the dungeon, the AI running the game grants sentience to Princess Donut. Carl and Donut now become players in a reality game, collecting loot, spells, and effects to “level up” and hook in their audience, their survival depending on ratings and the largess of their sponsors.

Entering new levels of the funnel in the successive novels, Carl and Donut gather allies in the form of other crawlers and NPCs, such as Mordecai, their game-guide and potion-maker. In the Dungeon Crawler Carl universe, science is highly advanced, making effects such as transformation and regeneration a physical reality. Thus, Donut becomes a talking, intelligent cat, while Katia, a fellow crawler, acquires a shapeshifting changeling form.

In the Faction Wars, the site of This Inevitable Ruin, eight alien-led armies compete to control a central castle in the city of Larracos, but the game structure has been destabilized by resistance from Carl’s team—the Princess Posse—and other human "crawlers". Complicating matters further, non-player characters (NPCs) have become sentient and formed their own faction, Team Retribution, to defend Larracos. Carl is operating under a constraint from a previous floor, in which a magical binding dictates that of Donut and Katia, only one can leave the ninth floor alive. To resolve this, Katia plans to accept a deal to become an attendant to a goddess on the twelfth floor, a choice that will seal her fate but allow Donut to continue. Carl, however, fears that the game will throw a loophole, making both Katia and Donut perish on the ninth floor. Carl’s survival is further challenged by his unwilling symbiosis with Shi Maria, an ancient spider-like entity now inhabiting a tattoo on his chest (in events in The Eye of the Bedlam Bride). As the Faction Wars begin, the other eight attacking teams form a powerful “Bloc” alliance, declaring war on both the Princess Posse and Team Retribution, setting the stage for an epic, large-scale conflict.