Wolf O'Donnell is a major character who is initially portrayed as a protagonist in Super Smash Bros. Crossover starting with Season 22. Wolf runs into Bowser after Bowser's encounter with Ganondorf, Yami Zelda, and Yami Kirby, and tells Bowser that R.O.B. is already on Captain Falcon's team, but decides to recruit Bowser for his own team to comfort him. Wolf assists the others in the struggle against Team Ganondorf and Team Meta Knight and even manages to defeat Ganondorf on his own. However, Wolf proceeds to attack Fox, as he entered the tournament to defeat Fox, even if that meant using his friends. In Season 25, Wolf reveals his Ascent Mode during the battle against the Nomadic Mechtogan. In Season 33, Wolf battles against Bowser twice due to the Heroes of Legend being corrupted by Phazon. In Season 34, Wolf once again participates in the Neo Smash Champion Tourney, but his motives are brought into question after he tells Mecha Sally that the Brawl Spectator Society and the other teams will no longer try to stop her from killing Sonic the Hedgehog. It is also revealed that Wolf's primary goals are to beat Fox, prove he is the strongest, and learn everything about the Smash World. It is later revealed that Wolf was hired by Nazo to help free Master Hand from Mephiles the Dark's grasp, which Wolf agreed to in order to gain knowledge of everything about the Smash World. Following Mecha Sally's defeat, Wolf recieves his reward, as Master Hand provides him with a book containing information about everything in the Smash World. However, Wolf is later revealed to be in league with Ghirahim as a member of the Revolutionaries, making Wolf an antagonist as a result. Wolf later reveals his fourth goal is to become the new Creator of the Smash World, and that he used Bowser in an attempt to achieve this goal so he could get his wish granted, but failed since the finals of the first Neo Smash Champion Tourney were cancelled due to Team Z and Team Wolf were the only teams qualified for the finals. Wolf then battles against the enraged Bowser and the other Heroes of Legend, but is ultimately sent to Tobi's pocket dimension due to his treacherous actions. Wolf is later freed by Tobi at Vile's request, but is soon arrested by the Dark Brawl Spectator Society due to his crimes against the Heroes of Legend. However, Wolf is later liberated by Sigma, who recruits him and King Dedede to help Sigma in his plans.
- Wolf is the rival of Fox McCloud.
- Despite being able to defeat Ganondorf on his own, Wolf used his Ascent Mode against the Nomadic Mechtogan. This probably means that Wolf only uses his Ascent Mode when necessary.