Originally Posted by Darth Ken0bi
I believe, and please correct me if I am incorrect, that Revan never really invaded the Republic for the same reasons as the "True Sith" intended.
Yep yup. It is strongly suggested that Revan fell of his own choice (knowingly embraced the Darkside) in order to protect the Republic. Unfortunately the corrupting power of the Darkside and the Star Forge proved too overwhelming for Revan and though he still strove to protect the Republic, towards the end of his reign he became little different than the Sith Lords of old.
Actually when you think of it, it's rather fortuitous that Revan was betrayed by Malak. It allowed him time to free himself from the domination of the Darkside, and with the help of Bastila (cannon version) he was able to awaken to the destruction he unleashed and ultimately redeem himself.