A free for all map where everyone fights everyone, which is nice since it's usually everyone against you. You're very gold starved until you can get the spell to destroy walls in the center of the map, and you can't get it until blue is dead (which unlocks bridges). It is possible to save your lvl10 orc in the beginning and use him to rush blue down if blue doesn't save his, or simply let him die on his own as he has no gems and will go in the middle to take the gems here, dooming him. After that, you can unfortify your gems, get an Avatar and really start your dungeon.

Meanwhile, green and yellow will certainly be at constant war, not really able to kill the other. In my case, green won and yellow constantly fed him corpses for the graveyard, which made green basically unbeatable in a straight fight considering his base creature limit is 55 compared to your 25 AND he gets tons of vampires on top of that. I tried abusing the scavenger room and used the prison/torture chamber left from blue (you can't make your own) but it took ages to go pratically nowhere.

Yellow finally died, and green slowly killed the white heart in the middle which triggered multiple spawns of lvl 10 heroes including an avatar in my base which I couldn't capture since green destroyed both the prison and the torture room.

You can also get 2 neutral mistresses to help, but against such an army I simply had to lame green with my avatar and kill his heart, which wasn't very fun.