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.

The game also includes 16 monster types (including seven new standard monsters and three new bosses) and a new campaign with 25 scenarios that invites the heroes to investigate a case of mysterious disappearances within the city. Is it the work of Vermlings, or is something far more sinister going on?

Gloomhaven: Jaws of the Lion is aimed at a more casual audience to get people into the gameplay more quickly. All of the hard-to-organize cardboard map tiles have been removed, and instead players will play on the scenario book itself, which features new artwork unique to each scenario. The last barrier to entry - i.e., learning the game - has also been lowered through a simplified rule set and a five-scenario tutorial that will ease new players into the experience.