Had Acererak beat Graz'zt in the finals, the ruler of the Tomb of Horrors (especially from the 2E "Return to the Tomb of Horrors") is just beyond all others
Though there were some very hard choices. Manshoon vs. Halaster, Lord Soth vs. Strahd, Verminaard vs. Artemis, Asmodeus vs. Graz'zt...all just very cool nemesis.
But true, love the bracket tournament and really excited to see who wins in the end ^^