The story seems a bit confusing, but I did that on purpose.

Nasus saved the Egyptian Empire from something that happened, no one knows what was that, but it destroyed the Earth. Only a few regions were lucky or powerful enough not to be gone forever. Those remaining parts merged themselves with pieces of other planets and a new world was created.
There are three Empires:

Egypt - ruled by Nasus, who is dead now
The North - ruled by The Duke, or Vladimir and his guard is Mordekaiser
Arrowtree - it has many regions together, but the main ruler is Ashe

I won't tell what destroyed the Earth and the other planets now, you'll have to continue reading.