I was playing a GC game with the empire and I was holding my own until the Consortium started spreading corruption through my planets. Soon I had structures being bombed on every planet. Do I have a unit available to neutralize corruption, or a way to stop corruption from spreading? I can't fight corruption with 50 star cruisers.
I didn't make it!
There are hero units such as Yoda, Obi-wan, Darth Sidious, Admiral Thrawn, etc. that can remove corruption around your planets though its going to cost you credits.