Leo0820 was the winner of the second Character Battle back in the Summer of 2003. He correctly predicted Cloud's championship run (no small feat; only 6% of brackets were able to get that right) and was rewarded with a very impressive 183 out of a possible 192 points, good enough to beat the next best predictor by a full 3 points.
In terms of Board 8 history, Leo is most famous for having a pretty awful username and also for not ever posting on Board 8.