Its been a while since I have seen one. Saw my first red evil vagrant tonight. If you don't know what they are you can read about them here. The only one I have never encountered is the red good vagrant. And I have only ever encountered the other three once a peace. And those were all in different versions of the game.
Here are what they look like:
I hope they have more odd ball stuff like this in DSII. But hopefully they are more powerful enemies that give better loot. They are not very powerful, and are some what rare. Or at least they used to be. They seem to appear more in the Prepare to Die edition.