Count Bleck (actual name Blumiere), known as Count Noir ("noir" meaning "black" in French) in the Japanese version, is the central antagonist-turned-anti-hero of Super Paper Mario. He is the last member of the 'dark tribe', and was a crazed being bent on using the Dark Prognosticus to destroy all existence, with his minions Nastasia, O'Chunks, Mimi, and Dimentio. He failed in his quest because his love, Tippi (or Lady Timpani) left and was no where to be found.
Several things occurred, but Mario defeated him with his friends. Just as the miserable Count Bleck found Tippi again and requested his own destruction before all existence was destroyed, Nastasia defended him from an attack from Dimentio. Dimentio stored Count Bleck away in another dimension. In the end, however, when Dimentio is defeated, Count Bleck and Tippi counter the Chaos Heart with their love on time to save all existence. The two of them disappear, but it is determined that, wherever they are, they are happy.
Peach has been kidnapped by Bowser so many times, it seemed like a good idea to mix things up--instead she gets kidnapped by this guy, Count Bleck! He then obtains the Chaos Heart by forcing Peach and Bowser to marry. All of this was predicted by the Dark Prognosticus, which Count Bleck carries with him.