Gloom

The Gloom is a hostile force that corrupts and consumes the world of Evenor, and breaks down reality into chaos. After the fall of the Architects at the hand of the Precursors, the Gloom began to consume the world, leaving the survivors to fight for the remaining scraps and ruins. While the Gloom is shown to be an ever-present malicious force that corrupts and consumes, a swirling maelstrom of Shadow and Chaos, the Gloom Dagger and the nature and powers of the Wayfinders show that the Gloom - admittedly through unique and comparatively extreme effort - can be controlled and manipulated at least partially, and thus taken advantage of. As described by Lord Halar, "the Gloom is not a monolith. It is a branching, moving, fragmenting mutation of reality. There are many layers within." With enough effort, a Wayfinder can intentionally plumb these deeper layers of the Gloom, though the deeper one travels, the more intense the Gloom's effects.

The Gloomfall

The Gloomfall is an apocalyptic event that occurred when the Gloom was introduced to the world of Evenor on a large scale. After the Precursors killed the Architects, they released the Gloom upon the world for unknown reasons. Following the intro, the game Wayfinder takes place one year after the events of the Gloomfall. The Gloom subsumed much of the world and continues to slowly consume the rest of it, and much of the land that remains has been cut off from each other, leaving isolated pockets of civilization. The Gloomfall is credited as forcing an end to the Mazewar, the large-scale armed conflict between the Avar Imperium and the Maze.

Lost Zones

When the Gloom consumes an area, it creates a Lost Zone, a shifting chaotic mess that changes every time. Lost Zones are described as not the exact location itself, but rather as a dreamlike recreation of the area it once was at the moment it fell to the Gloom, hence why the exact details and layout of a Lost Zone always change each time it is explored. Lost Zones are inherently dangerous because they're created by the Gloom, which is why only Wayfinders, who themselves are born of the Gloom as echoes of a fallen hero consumed by the Gloom, can reliably enter them safely. Non-Wayfinders may attempt to brave a Lost Zone, but it is considerably riskier. As a Wayfinder, to safely enter a Lost Zone requires three things: a Gloom Dagger, locating the actual breach to the Lost Zone itself, and a "connection" to that Lost Zone; the connection can be physical in nature, like an object or momento, or it can be less tangential as a memory or experience or some other ethereal yet real sensation.

Gloom Dagger

Wayfinders can control Lost Zones using Gloom Daggers, a device that lets one change what they see to a certain degree when they venture into a Lost Zone. Although the Gloom can be manipulated using Gloom Daggers, the Gloom in turn attempts to augment the Lost Zone with modifications to enemy damage, environmental hazards, and more.

Dark Star

The Dark Star is a mysterious structure of space rock and Gloom energy that hangs in the sky above Evenor. First observed years before the events of the game, it is clearly visible from the Highlands, for example, and has only grown larger over time. Occasionally, shards of rock from the Dark Star, referred to as Dark Star meteors and described as "falling stars darker than the night", will crash into the earth and begin corrupting the surrounding impact area with Gloom energy. These rock shards may be considered shards of concentrated Gloom, crystallized and punching holes in the sky as they hurtle into the earth. It is speculated that, somehow, the Dark Star exists as an alternative vector for the Gloom to enter the world, apart from the usual creeping growth of the Lost Zones and the Gloom's more corrupting efforts.

Corruption, Tears, and Conflict with the Beacons

Though persistent, the Gloom has its limits. The network of Beacons and Balefires left by the Architects hold the world together, and the Precursors breaking these connections are what allowed the Gloom to spread. So long as the Beacons remain lit, it cannot outright devour the world like it has the Lost Zones, as the light of the Beacons repel it. But it can instead turn to other tactics. For example, what the Gloom can't consume, it will attempt to corrupt and change. Flora and fauna can be influenced by the Gloom, altering its form or behavior. These "Gloom-touched" entities are markers of its more subtle pursuits. The Gloom can also be more forceful in its efforts, whether through the aforementioned Dark Star or by ripping tears into space for the Gloom to spill out of. Left unchecked, it can begin to break down the boundaries of reality, manifested as Gloom Tears. As opposed to a Lost Zone being an echo of a place consumed by the Gloom, a Gloom Tear is a rift into the void of the Gloom itself, effectively the elemental plane of pure Gloom.