When all enemies present on the table have launched their attack, it is the end of the round.
If any survivor is still alive and alone in a combat zone (no enemy left), the survivor is saved by the player.
Then, a new round may begin.
Enemies still present on the table remain where they are and will accumulate with the next hordes wave.
The player starting this new round is the one who plays right after the last active player (whoever next to the player that received the hordes wave).