Fawful is a reccuring antagonist in Super Smash Crossover. Fawful is first seen when he appears before Naruto, William Dunbar, Azula, DK, and Jigglypuff, though why he was there is unknown. William interrogates Fawful to find out if the microchip placed on the villains' doomship by Yami Bakura is still there, which Fawful says its still there. When Fawful hears that Naruto makes odd sounds, Fawful says they'll be the best of friends, and tells him there is still hope for Zombie Spider-Man, Pichu, and Fabia Sheen, but possibly none for Psycho Kirby or Sasuke Uchiha, saying that he heard Sasuke talk about how his plan is successful so far before Link and Zelda reveal everything. Fawful then states he can't believe that they fell for his monolouging. Fawful then assists Link and Zelda battle DK. Fawful reappears after a long absence in Season 21 along with Cackletta, when they are recruited by Yami Bakura and Uka Uka. Fawful reappears in Season 30 as one of the main antagonists, where it is revealed he helped Coredegon make the new zombie virus, helped Umbra stabilize the prototype, and helped Sasuke create his immunity serum. Fawful also reveals he orchestrated Fabia's hijacking of the Smash Bros. Galaxy so he could get all the alternate versions of Galactus in one place so they could be eaten by the zombies, therefore releasing Abraxas from imprisonment and causing complete chaos. When Abraxas arrives in Other World, Fawful has the Dark Star latch onto Abraxas and then breaks him down so he could integrate his DNA, as well as the Dark Star, into the heroes' DNA codes. Unfortunately, Fawful's plan backfires and he is forced to flee to the depths of the Home For Infinite Losers, where he is later killed by Coredegon. Fawful is later ressurected by Coredegon along with the zombie Fantastic Four, with the exception of Zombie Reed. However, Fawful is later killed by Mechtavius Destroyer while buying time for the heroes and villains to escape. Fawful reappears in Season 32 as part of a team formed by Mechtavius Destroyer to instill chaos within the heroes and to prepare the Earth for "the day of reckoning". However, upon Mechtavius Destroyer's defeat, Fawful abandons him and isn't seen again until after the tyrant returns to the Smash Bros. Galaxy. Upon learning of Mechtavius Destroyer's return, Fawful heads to the Comet Observatory to recruit the mentally unstable Rosalina to his side, having witnessed her destructive powers against the Heroes of Legend on his television and wanting to take advantage of that power. In order to convince Rosalina to join him, Fawful compliments her power and informs Rosalina that the only reason she lost was because she lacked her personal army, referring to the Lumas. When the Lumas object to helping a madman take advantage of Rosalina's insanity, Fawful hypnotizes the Lumas into obeying any command Rosalina gives them, regardless of the lack of morals. As a result, Fawful manages to get Rosalina on his side, albeit reluctantly. Unfortunately for Fawful, his victory is short lived thanks to Shadow the Hedgehog after he figures out Fawful's plan and frees the Lumas from his mind control with Rosalina's help. Furious, Fawful flees while stating the nightmare is only beginning. Fawful later interrupts the battle against Mechtavius Destroyer, and extracts the Dark Star from the heroes to form Dark Bowser. Fawful then engages in a brief battle against Dimentio before he is blasted by a stray blast from Mechtavius Destroyer, resulting in Fawful becoming a bug that is absorbed by the incomplete Dark Bowser. However, Fawful is later released twice during the battles against Dark Bowser and Rosalina, the first being when Gohan punches Rosalina so hard that she spits up the Dark Star Core, which Fawful has become, and the second being when Metal Sonic rams himself into Dark Bowser so hard that he spits up Fawful and shrinks to Bowser's size. However, when Sellon starts to taunt him, Fawful declares he has fury and transforms back into his Dark Fawful form, as he has had enough time to adapt to the Dark Star's power. However, Fawful is impaled by Ganondorf, who flings him into the ocean. Despite this, Fawful survives, and heads to Subspace upon sensing Master Hand's ressurection ritual. Fawful then makes his presence known, stating his shock at how far the Heroes of Legend have fallen and is impressed with Ganondorf's plan, but states that he will be the only god neccessary for the new world. Before he can cause any major damage, however, Fawful is sealed away by Sonic the Hedgehog until he feels like releasing him. Fawful is later released along with Ganondorf by Sonic. In Season 34, Fawful enters the Neo Smash Champion Tourney as a member of Team Corruption, and later joins the Heroes of Legend as an unofficial member due to Team Corruption being integrated into the Heroes of Legend as a result of their teamwork.
Fawful is the cruelest villain in the series, as he is determined to cause total chaos on the Smash World, and unlike other antagonists, Fawful doesn't have any specific reason for this, other than for his amusement.
Fawful apparently views bonds as weak, since he considers the Lumas as nothing more than an army at Rosalina's command.