Considering the fact the users of the force can survive through the force and continue to use it past the grave, the flood have no power over those with no physical body to control. Darth Nihilus could destroy any lifeform he wished merely by talking to it. Abeloth... well Abeloth is Abeloth. And then theyres the Sith, who some of which were capable of possessing lifeform a and mutating them to powers of the dark side using just their mind. Some Sith developed wormholes, while others learned how to bring back the dead. And then Star Wars has their most powerful weapon yet... JarJar binks, capable of ruining an entire universe with just his appearance!