Third Law of Magic
Magic permanently changes the creatures repeatedly exposed to it.
Long term exposure to magic has a permanent affect on creatures, depending upon the type of magic. The Portal Horse is the most well known example, due to the beautiful and strange colors and patters developed on their coats due to frequent Portal Travel and their exposure to these fields even before birth. Heavy exposure to dark magic, on the other hand, tends to twist creatures into nightmarish forms as seen in the inhabitants of Kogal Island. The young and the very old are more susceptible the effects of magical exposure due to their lesser physical defenses against the changes, but anyone can be effected given enough time with strong enough magic.
|Anti-magic drains magical reservoirs faster. Enchanted items will need more maintenance, and spellwork will require more Imperium. Locations with the strongest anti-magic exposure will no longer respond to magic at all.
|Dark magic twists and corrupts the creatures who dare to remain too long within its reach.
|The Calamity, Soul Poisoning
|Lightning-based magic had been known to disrupt the functions of the brain, bringing about early deterioration or other mental issues.
|Frequent exposure to portals and Portal Travel causes living creatures to develop multicolored swirls and patterns. These effects are superficial and have no lasting effects on the subjects. The changes are not genetic.