Mages

Mages are the name for an uncommon subset of many species who have the ability to manipulate the Mana stored inside themselves and their surroundings.
With certain genetic traits present, witches and wizards are able to consciously draw upon stored mana and directly convert it into other, more useful forms of energy, "shifting" the molecular arrangements of their surroundings. Most mages specialize in shifting back and forth between certain states of matter, with severely reduced efficiency and increased power consumption when working outside these sets of phases.
Despite being able to make the impossible mundane, talent and sheer power are not substitutes for skill, which has kept magic an exercise in higher education. Snapping fingers to boil water or glaring bent utensils back into shape are child's play, barely scratching the surface of what shifting can do in the hands of an expert. All mages must have a solid grasp on the properties of the materials being shifted, or inefficiently waste enormous amounts of their reserves to achieve the same results. More sophisticated research and military applications of magic can require significant interdisciplinary foreknowledge.
Understanding the healing arts, any liquid-certified healer trying to staunch bleeding will avoid unconsciously overpressurizing blood vessels, while a gas specialist could simulate hypoxia by removing the air from a interrogation subject's lungs, or save a drowning man by doing the opposite. A saboteur with a bit of gunsmithing experience could subtly degrade shipments of factory-new muskets to explode when fired. Fortunately, most mages aren't so sadistic to, say, boil the blood of enemy soldiers, using their specializations to instead, among other things, redirect artillery shells with gale force winds, throw fireballs, or raise mighty earthworks as the situation demands.
Ironically, despite their arguable superiority over baseline beings, mages throughout history have typically been an oppressed people. In fact, it may be the innate power imbalance that has led to various anti-magic movements rising and falling over the years, and an explanation for early societal development is that fear of magic caused rapid technological and societal evolution in order to either integrate or outcompete mages. Relations between mages and laypeople have varied wildly, ranging from the blood-soaked pogroms of the early Decian Remnant, to more benign examples, with wizards and witches commonly saving fellow revolutionaries in Vulkan children's tales, or dwarves being averse to designs that rely heavily on the magical sciences.
Predicting whether a child will have the traits of a mage is difficult. The ability to wield magic is neither wholly a dominant or recessive trait, and though the offspring of mage parents are much more likely to have those abilities themselves, it is not guaranteed, and vice versa. Since there is no way of determining whether an unborn baby will be a mage, this has led to some unfortunate recorded incidents for some families upon the realization that their child was "tainted."

Access & Availability

Mages are, depending on the species, a relatively common part of most societies' populations. It is known that while the child of a mage is more likely to be a mage, it is not guaranteed, and the genes that allow for matter-state shifting can appear even in a family tree that has never had a mage as part of the bloodline.

Discovery

Origins unclear. Historical evidence for the usage of magic can be dated back to the fossils that represent the beginnings of life on Sera.