It came out of nowhere.
Felix was flying through the shattered skies, enjoying the sights of the many portals, taking the occasional selfie. Then the threads of energy formed between the portals. Felix almost flew straight into one. That kind of thing never happened. And the threads multiplied and filled the air until one...
...Felix now is somewhere else entirely no idea how he got here. While flying through the wilderness the pain starts and eventually culminates with a blood-covered pebble coming out of his mouth. Which was only supposed to happen if Felix was somewhere else so far that the magic that allows his immortality couldn't reach and the only possible place like this would be another universe entirely.
An hour, he gives himself that much time and uses it, but by then Felix decides that crying isn't useful anymore no matter how much he wants to.
Instead Felix searches for civilization, since he is going to stay in this world for the foreseeable future.