Good. Bad. I'm the guy with the gun.
~ Ash Williams, responding to his doppelganger
A good twin or a good clone can be an attempt at creating a good version of a villain by science or magic - It can also be an alternative version of a villain from a twisted reality / timeline: On some occasions, it can be a literal twin of both the identical varieties. They can be also Good Counterparts meaning they share some similarities to the villains and their background.