Gloomhaven: Jaws of the Lion is a standalone game that takes place before the events of Gloomhaven. The game includes four new characters — Valrath Red Guard (tank, crowd control), Inox Hatchet (ranged damage), Human Voidwarden (support, mind-control), and Quatryl Demolitionist (melee damage, obstacle manipulation) — that can also be used in the original Gloomhaven game.

New players will find Jaws of the Lion an easy entry to the Gloomhaven setting with a simplified play surface - the book itself! - and a tutorial that plays out over five mini-scenarios to familiarise players with the game.