LA Ermor, well, people have managed to kill off Ermor before, they can do it again. In the past it mostly featured making sure AI is not up against it and ganging against it in multiplayer...
LE R'lyeh is a beast, but I've never seen a Vastness by turn 3. Actually, I've had worse luck than usual with their void summonings as the gate keeps sucking my mages into it.