I'm currently playing around with basing a D&D campaign off the idea that arcane magic is fading from the world.
I'm curious if the rule books have discussed the nature of arcane magic: Where does it come from? Is there a specific source, or is it simply an energy that exists (similar to the Force in Star Wars), that those with the correct blood line or knowledge are able to tap into?
I know a similar question was deemed off-topic some time ago, and Appendix N was quoted as being the answer in that question.
Where this question differs is that I'm not looking for the history of magic, I'm looking for a written description of the nature of the arcane.
I'm willing to accept answers from any edition, but would preferably like resources from 5th edition.
Best Answer
It varies by setting. For D&D5E, PHB (p205) describes it in general terms, then goes on to provide additional detail for the Realms - the Weave.
While the PHB implies the Weave exists in all settings, that particular term is specific to the Realms. It also glosses over material from previous editions, where it is more than the "essence" of Mystra, it actually is Mystra, the goddess of magic. Her death at the hands of Cyric and Shar, two other deities, is the cause of the Spellplague that altered magic to the system present in 4E, and her restoration during the Second Sundering is the reason it switched back in 5E.
In other settings, magic works differently (in Dragonlance, for instance, it's tied to Krynn's moons), but there is no official/dedicated 5E material for other settings.