Fawful is a recurring antagonist in the Mario & Luigi franchise. He is an eccentric Beanish who speaks using obscure metaphors and megalomaniacal ravings. He often describes food metaphors, such as the ever popular "Mustard of your doom!" One of Fawful's favorite phrases is "I HAVE FURY," which is a parody of mistranslations in older video games. Fawful is one of Cackletta's early followers, and rose through the ranks of her followers quickly due to his deranged attitude and evil genius. One of the default player names in Super Smash Bros. Brawl, FWFUL, is a reference to Fawful.
Mario & Luigi: Superstar Saga
Fawful's role in Mario & Luigi: Superstar Saga is largely him being a sidekick to Cackletta. He has an odd headgear which he utilizes in and out of battle. He is first seen in the opening cutscene, helping Cackletta steal Princess Peach's voice. Then, Fawful attacked Mario, Luigi, and Bowser on the Koopa Cruiser, and was defeated by the brothers. However, he managed to destroy the Koopa Cruiser, and they crashed into Stardust Fields.
Fawful then aided Cackletta with attacking Woohoo Hooniversity, and turning its inhabitants into monsters. It was in Woohoo Hooniversity where the two evil Beanish planned to use Peach's voice to activate the Beanstar. However, the plan failed upon the discovery that they had captured Birdo's voice, not Peach's. When Mario and Luigi found them in the Hooniversity, they destroyed Cackletta. Fawful sucked her soul into his headgear, and was about to attack the brothers when Prince Peasley intervened. Fawful landed in Stardust Fields, where he found Bowser and put Cackletta's ghost in his body (forming Bowletta).
Fawful was also in Joke's End, where he managed to steal the Beanstar from Mario and Luigi after seeing right through the fake Beanstar. When Luigi pretended to be the Princess, however, he and Bowletta were fooled, allowing Luigi to easily steal the Beanstar.
Fawful was the penultimate boss in Bowser's Keep, right before Bowletta. He was in a completely different uniform than before, now a skin-tight red suit with wing-like cloth. He also had a large robot that was shaped like his head, which he could go inside and shoot lasers from. Mario and Luigi eventually defeated him. The last time Fawful appeared was as an apparition in one of Cackletta's attacks during the final battle, implying that he died.
Mario & Luigi: Partners in Time
Fawful has a minor role in Mario & Luigi: Partners in Time. He runs a shop known as Fawful's Bean 'n' Badge located in the sewers of Princess Peach's Castle. Only Baby Mario and Baby Luigi can reach him, so he doesn't recognize them at all. He gives a long speech on how he plans to return.
Mario & Luigi: Bowser's Inside Story
Fawful is the main antagonist in Mario & Luigi: Bowser's Inside Story. He gives Bowser the Lucky Mushroom, which mind-controls him and makes him swallow Mario, Luigi, and several other Mushroom Kingdom inhabitants. Fawful takes over Peach and Bowser's castles, planning to find and use the Dark Star for his own purposes as well as getting revenge against the Mario brothers. In the end he is ultimately defeated by Bowser and the Mario brothers, after which he self-destructed in an attempt to kill the brothers along with himself.