Magic Staining/Discoloration

This is the effect of excessive magic usage on mortal skin. Deities that have mortal-looking true forms have similar looking discoloration, but theirs is a mark of being more magic than matter and always ends cleanly. Theirs doesn't tend to work logically- all deities' arms are colored in this manner, but as it leaves the arms it takes on more artistic patterns on the torso. These patterns always relate in some fashion to the deity's jurisdiction.
Most deities view those with extremely widespread staining as impersonating the divine, and the dislike that comes from that drastically increases the chances that the effected will be turned into a toji. Another factor to this is that, with enough magic capability and determination or persistence (or spite), a spirit can figure out how to ascend to godhood. While extremely rare, the mere possibility of it can make deities judge mortals with this type of staining far more strictly. They don't want a ton of (usually loose canon) spirits attaining godhood, and turn them into toji instead, which permanently bars them from that possibility. Toji, while exceedingly powerful, still have some restrictions.

Causes

It usually comes from either excessive pure magic channeling/use or excessive use of high-level magic. One major spell a week won't cause any (usually), nor will minor pure magic channeling most days. Usually those affected have careers that force them to use major amounts of magic

Symptoms

The staining usually creeps up the arms or legs, depending on where the magic is released from, though can also affect other areas of the body.

Treatment

There isn't really treatment to remove the staining, though there are some types of potions that can hide it for a limited time (exact duration depending on the potion). The only way to prevent it from spreading is to cease use of high-level or pure magic, or at least drastically reduce their use.

Prognosis

Under usual conditions, the staining progresses extremely slowly. Most beings don't use enough magic to trigger it, much less enough to have it progress much, even over their entire lifetimes. Most commonly, only fingers and toes are stained, rarely do entire hands or feet get stained.
Most toji had (at least) completely stained hands and feet while they were mortal, and the staining continues to spread throughout their existence.

Affected Groups

Magic Users

Prevention

Avoid using excessive high-level magic, essentially.

Cultural Reception

It depends on the point in time. Earlier on (when the other one and pink hair were actively mortal), beings visually affected were respected, admired, and idolized (to some extent-- in the way that celebrities are, but smaller scale). That holds true in the time of redhead, but only for certain people. People whom are deemed important by their communities are respected, but unknown or unfamiliar people are considered a threat-- that a person is skilled enough to even have staining is disconcerting. It just generally attracts dizzying amounts of attention.

Type

Magical

Origin

Magical

Cycle

Chronic, Acquired

Rarity

Uncommon