The General was the leader of MAGOG, a paramilitary organization. He had a vision to use MAGOG to rebuild civilization. His ends were altruistic, he didn't plan to take charge himself, and he knew it would take far longer than his lifetime, but his means were ruthless: he had no compunctions about killing anyone who stood in his way, or impressing innocent civilians into service to work for him as needed.
When one of his officers shot and seemingly killed Ryan during one such recruitment effort, Krysty made it her goal to kill The General and destroy MAGOG. She eventually did so, with some help; the train rolled off the edge of a cliff with The General aboard (Vengeance Trail).