Mario is the main protaginist of Super Paper Mario and the Mario franchise.
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Mario on the cover of Super Paper Mario

At the beginning Mario is out on a regular day with his brother Luigi, when Toad tells him Bowser has Princess Peach captive. Mario goes to rescue the princess, but it is revealed at the Wedding that Count Bleck is behind all the evil doing. Luigi, Bowser, Mario, Princess Peach, and Bowser's minions are sucked into a portal and the beginng of the story begins. Mario ends up in Flipside and has to pass eight worlds with the aid of Pixls and Tippi. On the way they encounter many things such as Flopside, Mr. L, and many of Count Bleck's minions. After Mario goes through and conquers all the worlds, then he is given the portal to Castle Bleck. There he and Tippi confront Bleck and fight the final battle against Super Dimentio. Afterwards, Count Bleck and Tippi get married and the Pure Hearts are joined together. The Pure Hearts end the Void, and it disappears. Mario and friends then celebrate at the end.