Aurora Deer

Marks are not unique to humans, and manifest in curious ways among select animals and even plants. Rarely does an entire species adopt Mark qualities, but the Aurora Deer have done so. Their antlers end in crystalline points which channel Girdle energy, though the deer's habitat usually makes for low-level effects, even with so many crystals mounted together. Using their horns for defense, aurora deer can deliver wicked electrical shocks to predators and run atop clouds, though this seems to be the extent of their abilities. Their name comes from the playful purple, green, and blue fires that dance about their antlers at night, serving as a warning to predators (though this can enrage moon bears).
Though it's not often spoken of, people born without Marks may have them added, though most rituals require a living donor- and the process results in their death. The Marks of the recently deceased can sometimes be used to make others into wizards, though this often taints their magic with dark energies (though the living sacrifice version can be similarly tainting). What makes aurora deer exceptional is that they alone among the animals and trees of the world produce crystals that can be used as Marks, and most produce an average of ten every year. The process of bonding with an aurora Mark is long and arduous, though this doesn't deter a stream of applicants from journeying to the extreme ends of the world (aurora deer prefer arctic climates, but the small numbers of them who exist have been spread to both north and south). More commonly their stones are used simply as small power stones, and closer to the equator they function quite well for smaller magical items. Aurora deer are exceptionally rare and are carefully tended and protected by migratory tribes who follow them in most parts of the world, armed with magical weapons powered by the Marks.