Magic connected us and 3 worlds combined. There should have been 2. Earth was not supposed to be one of them. And the worlds were not supposed to turn into swiss cheese full of connections everywhere either.

The Archmages responsible had dreamed of many things, but became victims of their own success, the forces of magic they had unleashed too powerful for any of them to survive.

Now huge portals litter the landscape, settlements, wilderness and deep sea alike.

(There is no System or god guiding anything)