Editing Fawful

After demolishing the castle, Bowser finds Dark Fawful in the castle's conference hall. Before the battle, Dark Fawful speaks like he did in ''Superstar Saga'', showing that he is losing his composure and acting rashly out of anger. He also says how Bowser has gotten in his way just like Mario and Luigi (referring to ''Superstar Saga''{{'}}s events) and that he now hates him just as much as them, causing Bowser to become annoyed and tell Fawful not to compare him to Mario. Fawful makes further reference to ''Superstar Saga'' by referring to Bowser (and, indirectly, Mario and Luigi) as "fink rats" for the first time since that game. Despite his use of dark magic, Bowser manages to beat Dark Fawful, he collapses into a bug-like form known as the Dark Fawful Bug and tries to escape, but gets inhaled by [[Dark Bowser]], causing the completion of the Dark Power and fusing Fawful with the Dark Star Core.

Fawful appears as a neutral-type Advanced primary [[Spirit (Super Smash Bros. Ultimate)|spirit]] in ''[[Super Smash Bros. Ultimate]]'', using his artwork from ''[[Mario & Luigi: Bowser's Inside Story]]''. Fawful's spirit battle is against [[Iggy]] (representing Fawful) and a green [[R.O.B.]] (likely representing a Mechawful), on the [[Prism Tower]] stage. The music played in this battle is "The Grand Finale" from ''Mario & Luigi: Bowser's Inside Story''. When equipped, the Fawful spirit gives an increase in power of electric attacks.

In ''Mario & Luigi: Bowser's Inside Story'', Fawful no longer has his bulbous antenna and he wears a black suit with black gloves, a red belt and grey sandals, which are hidden underneath his red cape with a partially grey collar. Most of the time, he appears on a green, circular hovercraft. Once he transforms into Dark Fawful by absorbing some of the Dark Star's power, his glasses turn red and his cape separates, revealing his suit, which has become purple with a black star on it, and no longer features the belt, gloves, sleeves or sandals. His coat gains a purple-red color scheme, and the collar becomes maud and spiky in appearance. In this appearance, he wears a revamped Vacuum Helmet on his head for the majority of time spent in this form. After being defeated by Bowser, Fawful loses his green humanoid body and becomes a small black head (although he retains his red glasses and wide grin) that can switch between four bug-like legs and two claw arms (after being inhaled by Dark Bowser, his arm form also has an antenna with a small Dark Star Core at the end). During the final battle with Dark Bowser, Fawful uses the power of the Dark Star Core to transform into a giant form (relative to Mario and Luigi's size during the battle), retaining his black head and its features but now having two tentacle arms, each with a hand with three clawed fingers, and three tentacle legs protruding from below his head with the Dark Star Core attached to the top of his head by an antenna made of black electricity. After being beaten, he reverts back to his smaller size, now without any of his limbs and with some of his teeth missing.

Fawful is shown to be very angry at times, but is also seen to be very devoted to Cackletta, whom he served with blind devotion in ''Mario & Luigi: Superstar Saga'', and is considered to be Cackletta's "favorite subordinate"<ref name="subordinate">{{cite|title=''Mario & Luigi: Superstar Saga'' manual|page=7|date=2003|language=American English|publisher=Nintendo of America}}</ref> in a manner resembling the archetypical "{{wp|Igor (character)|Igor}}" character. He is shown to be understanding of Midbus, who showed the same devotion to Fawful himself in ''Mario & Luigi: Bowser's Inside Story''. He enjoys taunting his enemies and believes he is never wrong. While initially content to be Cackletta's subordinate, he is shown to be quite self-centered when he becomes his own villain, theming many of his minions based on his own likeness, turning [[Bowser's Castle]] into a self-aggrandizing theater filled with merchandise of himself, showboating before Bowser's brainwashed minions, and refacing many of the decorations in the places he conquers. Even prior to Cackletta's final defeat, however, Fawful briefly considers the possibility of rising beyond a "toady" of Cackletta's, though he ultimately is beaten before he has the chance to consider it further.

Fawful is the second boss of ''Superstar Saga''. When fighting him, he does not have much [[Heart Point|HP]]. Being an early opponent at this point, Fawful also does not have a large variety of attacks. In his first attack, he shoots green energy balls at the Mario Bros. from his Headgear, and in order to avoid the attack, the player must look at the color of the text when he calls the heroes "fink rats". If the text is red, he shoots at Mario, but if the text is green, he shoots at Luigi. Later in the battle, Fawful says "Have you readiness for this?!?", in which he shoots two energy balls - one at each brother. The color of "this" indicates which brother Fawful targets first. After 18 points of damage, Fawful's helmet falls off, making him unable to shoot fire balls. In this state, Fawful has only one other attack; He can run up to one of the Bros. and try to roll into him. This can be countered by a well-timed jump.

|opponents= [[Iggy]], [[R.O.B.]]

|SpaE2=Fawful

|SpaE2N=''Partners in Time''

|SpaE3=Esbirro Jijí

|SpaE3N=''Superstar Saga''

|SpaAM=Lord Fawful

|SpaEM=Master Fawful