In my current game, I destroyed a mining starbase belonging to the Dark Yor. I only wanted the military recource that they were mining, and of course this began a war with the Dark Yor. After a few turns I offered them a peace treaty, in exchange for a peace treaty from them, their only planet, Dark Yor III, and all of their money. They accepted and that was the end of the Dark Yor.
This has happened with them before so if they are in any games that you (anyone reading this) have, attack them, then offer a peace treaty in exchange for their planet and as much cash as they will give you. If you have any sort of decent military power, they should agree.
I'm not sure that any race should give up their last and only planet in exchange for a peace treaty. It's basically surrendering.
