The Hellmouth, a location in the Ocean of Storms on the Moon, is the main entrance to the vast Hive catacombs that run beneath the surface. The titular Hellmouth dominates the area, a gaping pit filled with a greenish miasma and ringed with structures from both the recent Hive resurgence and Golden Age human activity.
- The concept art of the Hellmouth that appears in this article was the very first art asset created for the Moon and was used as the starting point for all subsequent Moon assets.
- Bungie Lead Environment Artist Sam Jones described the Hellmouth as having "one function only: to ask of the player what lies within." Because Hive architecture generally is meant to have an "accentuated sense of scale, menace, and a hefty touch of the exotic without being too alien," the Hellmouth "takes these principles and expands them to a colossal scale." Early concept art for the Hellmouth was intended to convey "appropriate themes for the Hive, including mystery, darkness, evil, strength, and militarism."