That was the thing he would only be a practitioner of the dark side of the force holding no attachments to the sith any more. He wasnt neccesarily happy to be under the tutelage of his master and with the event he feels he has been set free. His goal is going to be to find the cause of the light the thing that set him free and let him start his life anew. He would continue to use the darkside of the force for survival. It would be the only part of the force he had ever been a part of and its possible he could be swayed to the jedi side. But he wouldn't be a part of the jedi/sith fights