And then what?

One thing that I've found in common with big time villains is their desire to destroy world after world. Sounds like something an evil person would do sure, but what happens if they actually succeed in doing so? I know theoretically, it's impossible for them to destroy every single planet in the known universe within their lifespan (or maybe not), but even if they do, what will they do after?

Probably kill themselves

well, that escaladed quickly

Well they already killed everything else in the known universe. Their appetite for destruction would never fully be quenched and so the only thing left for them to destroy would be their own existence. I think it escalated a quite the appropriate pace for characters that have that mindset.

Notice how they would destroy all the planets but leave all the moons undamaged. I'm sure they will have some kind of fortress on a moon with some surviving human/aliens in order for them to feel like kings of a non near extinct universe.

@humanrocket: I've actually never thought of that.

@eric8a92:

Enjoy the damn quiet for once.

The Dragonlance books actually had a story where this occured. Raistlin killed all the gods in their world.

Usually the type of villains who come up with those type of schemes are suicidal, or just f**king Yonkers.

Go to another Universe and start all over.

I think they would savor the moment, just sit on a huge pile of ash and just think "Yep, I did this". After that, I have no idea. Find another world, gloat, then do the same thing again?