- "To you, I must say AHOY! I was wise to choose you as my captain! Ahoy to me, as well."
- ― Flavio
He is in possession of many a ship, particularly, his prized S.S. Flavion, which was used by himself and Mario to travel to Keelhaul Key. To the dismay of Flavio, however, the ship was destroyed by ghosts on that aforementioned voyage.
Flavio is perhaps better known for his high level of narcissism; he enjoys believing that he is a fearless, brilliant man, idolized and envied by the many. Unfortunately, he is not actually liked and quite frankly, the citizens of Rogueport would rather see the back of him. Flavio can been seen in the Inn of Rogueport where he can be seen singing to himself. After Mario meets up with him and askes what he lacks in life, Flavio is willing to take him to Keelhaul Key. However, Flavio says that they need a navigator and Pa-Patch recommends Admiral Bobbery. After Mario comes back with Bobbery, Flavio and the rest set out for Keelhaul Key. During the journey, Flavio writes down the events until one night that everything turns dark. Flavio, still talking greatly about himself, doesn't notice it until the last second and the ghosts sink his ship taking everyone else down with it. Flavio and the other make it to shore where they set up. However, Flavio soon gets into an argument with Pa-Patch but is quickly stopped by the arrival of the ghosts. Flavio orders Mario to take them down and he does so and Flavio waits back in base while Mario presses forward. Eventually, Mario talks with Flavio again saying Admiral Bobbery needs Chuckola Cola as his last drink. Flavio offers to give it up but wants something native of Keelhaul Key to replace it. Flavio accepts the Coconut and hands over the Chuckola Cola (which actually belongs to Bobbery). Later, Flavio is needed again but doesn't want to go and askes his crewmates that they still need him around. However, his crewmates are eager to see him go and Flavio joins Mario's side for a short time. They eventually reach Skull Rock and Mario requests of his Skull Gem which Flavio reluctantly hands over. Flavio's singing gives a clue for Mario and he finds a way into the Pirate's Grotto and Flavio picks up his Skull Gem and heads off wishing luck for Mario and the others. Eventually, Lord Crump begins attacking the island and Flavio, in an act of braverly, askes Mario to take him to Cortez. Flavio then speaks with Cortez and hands over the Skull Gem to activate the Black Skull and sails out to Crump's battle ship. Mario's team is victorious and Flavio finishes writing in his book.
- Flavio is the first person of a Paper Mario game to join Mario without actually becoming a permanent partner. The second will be Luvbi from Super Paper Mario, the third will be Toads and Wiggler Segments from Paper Mario: Sticker Star, and the fourth will be a Shy Guy from Paper Mario: Color Splash.
- Flavio's love for adventure behavior is somewhat similar to Kolorado's from Paper Mario. Also, his arrogant behavior is similar to Flint Cragley's who will later appear in Super Paper Mario.
- He is also known to be the editor of the mysterious magazine Foppish Gourmet Weekly.
- In the final RDM issue of the game, it states that Flavio is 25 years old.
- Flavio is the "Professor Kolorado" of Paper Mario: The Thousand-Year Door, however, in sharp contrast to Kolorado's recklessness inside the volcano, Flavio is a coward.
- Flavio's name is most likely derived from the Latin word flavus, which means "yellow", a reference to the color of his skin, as well as his cowardly nature.
- Flavio talks in a slightly similar manner to Fawful, except more straightforward.
- During Chapter 6, Pa-Patch (who chooses to stay on Keelhaul Key) sends Mario an email saying "Every now and then that cretin Flavio spits out some bit o' drivel about treadin' water instead o' seizin' life, but I just tune 'im out." This makes it sound as though Flavio was staying at Keelhaul Key as well, when it is clear he returned to Rogueport after Chapter 5 and is not seen on Keelhaul Key again, although it is possible that he often sails to Keelhaul Key with Cortez as Bobbery does after the game's final boss is defeated.
- Cortez' threat to Flavio mirrors similar threats made by Moe Syszlak from The Simpsons whenever he was hit with a prank call by Bart Simpson, which was itself derived the Red Tube bar prank calls.
- There is a glitch that allows you to keep Flavio for the remainder of the game. It even causes some strange side effects in the cutscenes as well as in the "Super Mario Bros." room in X-Naut Fortress. More info on said glitch can be found on the video to the right.