Weegee

Weegee is the counterpart of Luigi and is the main antagonist of Paper Mario: The Next Chapter. He was created by Cackletta to destroy Mario and his friends.

Biology
Weegee is known to be Luigi's strength and pride, even though Luigi has a phobia of ghosts (portrayed in Luigi's Mansion). In the middle of the game, he managed to hypnotize Bowser into destroying Mario. Other than that, not much is known about him.

The Splitting
While Mario and his friends were about to dig into some delicious pizza, Cackletta appeared and zapped Luigi, causing him to split in two: his normal Mario loving self, and Weegee! After that, Mario decided to get out of there while they had a chance. Now he has to embark on a journey that willl test his bravery.

The Plan
When Cackletta finally decided to reveal her plan to Weegee, he was star-struck. He realized his goal in life: to destroy Mario.

The Defeat
After a long journey, Mario finally managed to make it to Weegee and began a battle for the record books. After the battle, Cackletta began to destroy Weegee when Shadoo got in the way and saved Weegee and Luigi. Then Cackletta took the Chaos Gem and became a horrible beast she called Chaos Eternity.

Trivia
Although Weegee in Paper Mario: The Next Chapter is Luigi's counterpart, in real life, Weegee is just a name Luigi gave himself by the pose he makes while standing still.