So why does he have heralds, anyway? IIRC (from one reference 20-30 years ago), it's to prepare his victims for their deaths. But what are they going to do? I can't see any world having enough spaceships to evacuate everybody; the result has got to be worldwide panic and fighting over who gets to leave (assuming they have any ships good enough to take them somewhere they can survive). Just the sort of thing to entertain the biggest sociopath ever.