Some things defy explanation. There exist other forces, maybe somewhere out there, maybe hiding within us. There are beings of vast and wondrous power and you, you alone have an edge over them. Draw out the circle, speak the incantations, and hope that the bindings hold. You have work to do, but you won't do it alone.
The summoner is a new base class for the Dungeon World system. The summoner binds and controls fantastical creatures, designing individual summons from a list of over 20 traits. For your edification, three sample summons are provided below:
The Great Bear Polaris, Whose Roar is the Thunder: Large, Destructive, Domain (weather)
Kalastara, The Five-Faced Weaver of Fate: Dominus, Omniscient
BEES THAT ARE ON FIRE: Amorphous, Flying, Elemental (fire)