The Diablo Universe, or "in-world" are the terms that encompasses EVERYTHING related to this franchise/Intellectual Property. Sanctuary is only one world within this universe.
Distinction
This article is here primarily to explain the distinction between the world of Diablo (primarily Sanctuary) and the all-encompassing idea that is the whole universe. Every single plane of existence, world, person, item, and even idea related to the "in-universe" universe is highlighted when someone speaks of the "Diablo universe" rather than just the world, or other minor bits.
This also relates to all information found in all three games, not just Diablo III, but Diablo II and Diablo I as well.
In-Universe
The term in-universe means that particular piece of information is "real" to the people of this world. This is often closely related to what is and isn't canon. Anything learned from meta-information such as deducting plot lines is not in-universe information, even if the information itself may be canon.
In-game information is also related, it's stuff like how much armor does a shoulder pad give and stuff like that.
Get What You Want
In terms of usefulness of information, this article is not very important at all. If you want to know more about any particular part of the universe, head out in the wiki!
- Diablo 3 Basics - You were probably looking for this anyway. All things new, in bitesize chunks.
- Classes - The new and old classes.
- Monsters - The big baddies of the Diablo universe.
- Items - All sorts of in-game items.
- Characters - The story-bound characters of Diablo. Not classes!
If you come across this page and think a link to a specific section owuld fit well here, just go ahead and add it!