Spirits are sentient beings originating from the metaplanes. Under some circumstances, they can cross the gap between their dimension and ours. A lot of magical tradition manage to invoke a specific set of spirits.
* Shamans and Druids invoke Nature Spirits
* Toxic Shamans invoke Toxic Spirits
* Insect Shamans invoke specific Insect Spirits (cf, Chicago, and Bug City)
* Hermetic Magicians invoke Elementals
* Wujen invoke Spirits of the Elements and Ancestor Spirits
* Tír na nÓg followers of the wheel are rumored to invoke the Wild Hunt at a high rank.
* Initiates, who use Blood Magic are able to invoke Blood Spirits
* Houngans, Mambos and Voodoonistas may summon the Loa
Some spirits, however, don't need the commands of a magic user in order to come into our world
* Baba Yaga
* Bean Sidhe
* Brocken Bow
* Corpselight also known as the will o' wisp
* Free Spirit
* King Frost
* Man of the Woods
* Nomad Spirit
* Wild Hunt
Some of these are twisted or even toxic ones, while other so called "Wild Spirits" are only extremly strange, and metaplanar creatures like the Shedim, Horrors or Nomad Spirits are some of the most possibly dangerous magical hazzards to metahumanity.