MarkB
Legend
So, apparently Bahamut and Tiamat made the First World together (after making Sardior to be their assistant on the project), and all other worlds have echoes of it, which allows DMs to import setting materials from one world to another and explain them away as "echoes".
Wyatt is very keen on the whole shared multiverse thing. Which is fine, but really doesn't need to be canonical for every setting.