Degrees of 'Gloam', the exomagic infestation of the Twilight Beast, Un, are separated into six stages. These stages are: Nascent, Minor, Major, Irreversible, Overwhelming, and Total.

Exomagic 'deposits' into the arcane current of an area when it is used, a small proportion of every spell cast lingering like nuclear fallout in the vicinity. It clogs arcane channels like clots, slipping between and choking the gears of the Cosmic Clockwork and eventually warping it into something else entirely. Gloam, as this effect is called, is reversible, though only a few Exomages among the Vressian ranks seem to know how to reverse it manually, and past stage three it is irreversible even by these select Vress. Exomagic naturally clears away from an area over an order of centuries or even millennia.

STAGE 1: Nascency
In this stage, exomagic infiltration is minimal. Evidence remains of spells cast before, but enough time has passed or it originated from such a minor spell that it's utterly benign. Little to no concern, beyond the knowledge that an exomage was at some point present in a location in this stage.

STAGE 2: Minor
In this stage, the effects of the Gloam begin to set in. A few strong spells are enough to bring an area into this stage. Arcane mages may or may not begin to notice subtle disorder when casting; casting in an exomagic-infested location is sometimes described as 'slippery'. Spells kick off with just a bit more or less force than intended; a minor mistake that might not have prevented a spell from casting before now results in fizzling sparks; and overall, something just feels off about trying to cast Arcane magic in an area like this. Some particularly sensitive people, especially astralists, report feeling a strange malaise.

STAGE 3: Major
In this stage, clear evidence of Gloam begins to present itself. Some people who are magically sensitive might feel pins and needles. A very faint, cloying sweet scent sticks to the air and makes it almost nauseating to breathe in over extended periods. An extremely faint shimmer is present that most people would dismiss as an optical illusion or a trick of the light, invisible to all but those who are looking for it. Standing inside of this field for too long can cause headaches and vision problems. Arcane casting is shockingly difficult; an experienced spellcaster retains most of their power, but might find spells weaker or less accurate than usual.

STAGE 4: Irreversible
In this stage, the Gloam begins to overtake reality. It takes thousands of years for a location in this stage to recover, if it does not progress to later stages. A thin, oily sheen clings to almost every surface. Most plantlife begins to die out, while other species experience an inexplicable surge in vitality. Processes of decay speed up dramatically; buildings and constructions begin to experience rapid wear. That nauseating sweet smell is almost acrid, and certainly is no longer a mere background scent—it now easily provokes vomiting. Arcane casters find it increasingly difficult to manage any kind of magic, and even other kinds of casters notice that their magic is less effective. Exomages, by comparison, are orders of magnitude more powerful in these spaces. The Grey Pass is considered a Stage 4 location.

STAGE 5: Overwhelming
In this stage, the world under one's feet has begun to collapse. The land rapidly warps in shape. In cities, this manifests in horrifying ways as they seemingly rearrange themselves at random, entire blocks vanishing with their occupants and new ones appearing with entirely new occupants. Swathes of land 'sink' into the exomagic, becoming impossible to escape once entered and separating from the rest of reality. A plot of forest land becomes a hole webbed across a thousand times over by ultra-vital kudzu. The sky turns a brackish green. The Twilight Beast begins to crown, into a world finally reshaped that its image might make sense. Arcane casting is impossible and most other kinds of casting are extraordinarily difficult. Exomages find that reality bends and warps at their very touch. Time begins to break down as we pass into Stage 6.

STAGE 6: Total
The Twilight Beast emerges, and vanishes, all of the afflicted land in tow. As much land as was poisoned by the exomagic disappears in a blast of white flame, scoured from reality by the Architect's light. The Sunken Plane is considered to be a Stage 6 location.