A Permanent Enemy

So maybe this is just a thought exercise or maybe it creates a really cool enemy for some campaign: So there is this street rat. He becomes a runner for a minor gang leader in town. The adventuring party is hired by the local chamber of commerce or merchants’ guild to put an end to these thugs. They defeat the gang leader in his lair, but the kid escapes. Maybe they don’t even notice. The kid then starts running errands for an evil wizard. He becomes the wizard’s apprentice and learns some spells. When the party defeats the wizard, the apprentice bamfs out (or escapes in some other fashion). Maybe he gets away with a few choice magical items as well. Maybe one of them the party was expecting would be there, so when it doesn’t show up, they know something is up. So next he finds a major warlord trying to get some magical power. He helps this guy, but the warlord hates that the kid is such a wimp, so he beefs him up. This time when the party comes the warlord rushes them with some huge sword/axe (attracting all the attention and allowing the kid to once again escape). Now you have a fighter/mage/thief, and he decides to become the villain himself instead of relying on others. Not only is he pretty powerful at this point, but he has learned what doesn’t work. He should be able to come up with clever plans, not just the one-dimensional ones used by his previous bosses. Further, he has seen the adventuring party and likely knows who they are, what their skills are, and how they tend to fight. This way if you as GM “cheat” and design things specifically to defeat your players’ characters, it is fair and just because the kid has seen them fight three times. Just remember - One bad guy always gets overwhelmed by the multiple good guys. One guy who can do it all will not be able to defeat the party singlehandedly, though he stands a much better chance at it than just about anyone.