Sorcerer King is a new direction for 4X game design, pitting the player against a single overwhelmingly powerful enemy instead of a set of evenly matched factions racing for abstract victory conditions.
Think of the Sorcerer King as the evil mage who won the last traditional 4X game. He has already conquered the world. His enemies (including you) are scattered, their armies broken and cities torn down. His dark minions have free reign to terrorize the survivors everywhere except a few tiny outposts of civilization (like the one you start in) too insignificant to crush.