Realm of Titans
Magic and Mages
In this world, magic works somewhat differently from a usual D&D campaign. Spells and other magical influences draw from the energy of other Planes of existence to create their effects. Currently, the only known Planes from which energy can be drawn are the Aether Plane and the Abeyant Plane, although there is no reason to believe that these are the only ones that exist. The Plane that humanity inhabits is known as the Material Plane.
The Aether Plane is a Plane of roiling energy that is the most common source of energy used by mages. The Titans possessed the ability to draw energy from this Plane freely, and their deaths weakened the barrier between the Material Plane and the Aether Plane enough that humans and other lifeforms could draw on its energy as well. Some even theorize that this is where the Titans originated. Due to the incredibly volatile nature of the Plane, being sent to it results in near-instant death.
The Abeyant Plane is a Plane of mostly-dormant, yet extremely powerful energy. Abeyant energy is far more powerful than Aether energy, yet it is also more unstable, and every time the Plane is drawn on for energy, it is brought slightly closer to a violent upheaval. For this reason, the use of Abeyant energy to fuel spells is highly discouraged, if not outlawed, by most of society. While nobody knows for sure exactly what will happen when the Abeyant Plane erupts, there is little doubt that it will be a highly destructive and disastrous event. Those who regularly use the Abeyant Plane for energy are known as Abeyancers. Due to the mostly-dormant state of the Abeyant Plane, being sent to it presents little danger.