There are three things that spellslingers do that no one else can: tap into mana to cast spells, interact with spirits and bind those spirits to their will, and interact with (and travel to/through) the Astral Plane.
Spellcasting is as you would expect. Spellslingers can learn various spells, from offensive (fireball, acid spray) to defensive (heal, armor) to everything in between (manipulation, invisibility, confusion).
When the world Awakened and the Mayan Sixth World began, one of the more drastic changes was the discovery of the Astral Plane. Astral space mirrors the real world, but with more of an emphasis on life and emotion than material. While viewing the Astral Plane (either indirectly or by leaving one’s body), a magician will view non-living objects as blurry and indistinct, while all life is brilliant and surrounded by its own personal aura (more on auras later). Astral Space ends with the upper atmosphere (any magician trying to travel beyond either dies or goes insane). Non-living matter can be traveled through without incident, but auras cannot be passed through. The Earth has an aura, leading many mages (particularly shamans) to assert that the Earth (or Mother Earth or Gaia or etc.) is living entity.
All living creatures have an aura, as well as all spirits and magical constructs. The more “alive” something is, the stronger its aura (a street samurai has a weaker aura than a standard person, due to replacing most of their living matter with chrome). This aura can be read for emotional content, truthfulness, and other aspects of a person. Additional, strong emotional events (murders, riots, toxic waste dumps, etc.) can leave a lasting aura in an area, and magic (spirits and spells) can be traced through Astral space back to the practitioner who created them.
Living in, around, and/or beyond Astral space are spirits. They are of six basic types: fire, air, earth, water, man, and beast, though different practitioners call them different things and they appear differently based on who summoned them. These spirits can be bound by a practitioner (either until dawn/dusk or for longer services, though they resent being bound for long stretches) to perform services. These services include using their magic abilities, following someone, guarding an area, and more.
Traditions: Hermetic Mages and Shamans
The two primary traditions of spellslingers are the hermetic mages and the shamans. There are as many traditions as their are cultures (Christian theurges, djinn, etc.), but the two most common in Seattle are mages and shamans.
Hermetic mages are the analytic spellcasters. To them, mana is a force that can be understood and controlled. Spirits are viewed as tools to be controlled (and if you break your hammer, you don’t feel bad for your hammer).
Shamans are more like tribal mystics (and many, but not all, are Amerindians following their tribe’s ancient traditions). Mana is a gift from Gaia, and spirits are ancient beings, to be treated as friends and allies.
The choice of a mentor spirit is the most important choice a spellcaster will make in their life, as it influences not only their magic, but their goals and personality. For instance, a shaman of bear will strive to be an honorable warrior, while cat is a proud sneak and trickster. There are also non-animal mentor spirits (such as the Fire-Bringer, Mountain, Seducer). Not having a mentor spirit is a decision as important as choosing what mentor spirit.