Count Vaart is the last champion to encounter. Since the game gets more difficult as you process, he is the hardest to defeat. Like on the other planets, you must have 4 fragments in order to enter the Gloglans main arena.
Count Vaart is not only super obsessed with winning, he performs horrible experiments on other creatures on Gloglans (ex: deforming their bodies). In the final battle in the beast, he states that he was "a little too hard to swallow" & possibly held onto the creature's uvula. Thus, he is the most sinister other than corrupted Yeedo.