Luigi
From Paper Wiki
Luigi is Mario's younger brother in the Mario series.
Paper Mario
In this game, Mario and Luigi are invited to Peach's party at her castle. Before Bowser had taken over her castle Luigi managably escapes. For the rest of the game, he is at home begging Mario to go on the adventure with him. If Mario gains the Super Boots and sees a loose panel at his house, it is revealed that Luigi has a diary.
Paper Mario: The Thousand Year Door
While Mario saved Princess Peach and got the Crystal Stars in Paper Mario: The Thousand-Year Door, Luigi also had a mission of his own. After every chapter in the game, Mario can hear Luigi's story in Rogueport.
When telling Mario the story, Luigi exaggerates and tells a few lies to make the story better and make himself sound much more heroic, but Luigi's partners almost always secretly tell Mario what really happened. Later, Luigi gets interviewed and 5 Super Luigi books are sold.
Luigi's adventure involved rescuing Princess Éclair of the Waffle Kingdom from the Chestnut King. Luigi's story sounded extremely similar to Mario's in most aspects. He usually messed up during his adventure, such as accidentally knocking his partner Blooey the Blooper into lava.
Oddly enough he also appears in the audience when in battle. He also cheers Mario on during the final battle with the Shadow Queen. One of the word bubbles says "YOU GO BRO" in green letters.
