Wolf O'Donnell (ウルフ・オドネル, Urufu Odoneru) is a character from the Star Fox series, he is the leader of the Star Wolf team, the rival team of Star Fox. He is a playable character in Super Smash Bros. Brawl. Wolf made his first canon appearance in Star Fox 64. Very little is known about Wolf's past, or how he received his eyepatch. Wolf is a secondary villain taking orders from Andross, though since his appearance in Star Fox: Assault Wolf has had occasional stints as an anti-hero somewhat similar to Wario.
Wolf was originally going to appear in Star Fox 2 for the SNES. However, although the game was completely finished, it was canceled due to the upcoming release of the Nintendo 64, but some of its features were used in Star Fox 64 (Lylat Wars in PAL territories), including the Star Wolf team.
Wolf made his first canon appearance in Star Fox 64. He, along with Leon Powalski, Andrew Oikonny, and Pigma Dengar, formed team Star Wolf and were hired by Andross to destroy the Star Fox team led by Fox McCloud. Throughout the game, the player can battle Star Wolf up to two times, though there are three different battles with them overall.
Nine years after the events of Star Fox 64, in Star Fox Assault, Wolf became known as Lord O'Donnell among criminals at the Sargasso Space Hideout. When team Star Fox went looking for Pigma (who stole a Core Memory earlier in the game), Star Wolf (now consisting of Panther Caruso, Leon, and Wolf) went to destroy team Star Fox for invading Wolf's organization. Star Wolf was defeated in the battle. When the threat of the Aparoids was rising, Wolf arrived on Corneria to save Fox from the Aparoids (Wolf said the only reason he saved Fox was so he could destroy Fox himself). After that event, Star Wolf provided backup to Team Star Fox two more times in the game, including the final battle. Because of all of this and his respecting attitude, many have viewed Wolf to be an anti-hero. After the Aparoid Homeworld exploded, team Star Wolf was nowhere to be found, although Fox speculated they were alive. This was later proven in Star Fox Command.
After the events of Star Fox Assault, Team Star Wolf was confirmed to be alive and continued their lives of crime. However, they were noticed by the Cornerian Military. As a response to their crimes, a bounty reward was set for each member. (Wolf had the highest bounty set at $3,000,000). To avoid attention, they set up a base on Fichina. After this, they sought to remove their bounties and were tired of being seen as villains. Star Wolf then began to plot out a way to defeat the Anglar Empire. Afterward, the team split up. While Leon and Panther went to Katina, Wolf was presumably researching a device that Andross built which would neutralize the toxicity of the Venom Sea allowing them to infiltrate the enemy base. Team Star Fox found the device on Titania first, however, but Star Wolf made the enemy flee from Venom, allowing Star Fox to finish the enemies off. Star Wolf was not seen again until the ending, where Krystal requests Fox to remove the bounties off of their head.
In Star Fox 64, Wolf spoke in an accent in which he sounded like an English narcissist; in Star Fox Assault, his voice differs in which he speaks in a gruff accent and acts more like a space pirate. His speech in Command was similar, except that he occasionally howls and growls. In SSBB, his voice is similar to the accent he used in Assault.
According to a source relaying information from early 2002 Famitsu articles, Sakurai planned to include Wolf alongside Bowser, King Dedede, and Mewtwo, as hidden villain characters. Budget and time constraints however forced Sakurai to scrap these characters. 
In the opening sequence to the game, there is a short moment where Fox, piloting his Arwing, crosses paths with Wolf in his Wolfen. A mugshot of the two characters in their cockpits is briefly seen. In early days of the game's release, this led to much speculation of Wolf playing a role in the game, perhaps as a playable character. However, this was not the case, and Wolf makes no appearance in the game outside this opening sequence, not even as a trophy (though he is mentioned in the Wolfen's trophy description). Information from early 2002 Famitsu articles did reveal though that when Sakurai decided to add clones to the roster, Wolf was initially considered being included as a Fox clone. With shared animations however, Sakurai felt Wolf would just be received as a "gray-colored Fox", so he decided to include Falco as a Fox clone instead, as Falco was a completely different type of animal who provided a greater visual contrast.
Wolf is a secret character in Super Smash Bros. Brawl who can be unlocked by playing 450 VS. Mode matches, clearing Boss Mode with Fox/Falco, or a secret door in The Ruins stage of Subspace Emissary. His look is based on his appearances in Star Fox Assault and Star Fox Command.
Wolf seems to be very based loosely on his rival pilots Fox and Falco, but despite his general perception as being another Fox clone, his attacks are mostly new, with the exception of his Final Smash. All of his standard attacks are completely different, which involve the use of his claws or legs. While his special moves follow the same basic format of Fox's, they still have significant differences. Wolf's Blaster has a completely different appearance, its shot in a completely different animation, shoots a completely different projectile that functions a bit differently, and Wolf's Blaster has a bayonet attached that deals melee damage; the only real similarity with Wolf's Blaster is that it uses the same type of weapon. His Wolf Flash attack is like Fox's Fox Illusion, but it moves diagonally rather than horizontally, while animating differently with different aesthetics, and it functions differently, as Wolf starts weak, but ends in a powerful sweetspot that can meteor smash. With Fire Wolf, while it has an identical name to Fire Fox, it is a kicking attack that scores multiple hits on the opponent, that also has no fire effect whatsoever despite its name and no charging period like Fire Fox, thus leaving the move's similarity in-name only. His Reflector is also a bit different, as it has different aesthetics, and some functional differences, such as the significant intangibility frames it produces that give it capability as a pseudo-counter, and it sends all projectiles back at twice the speed of their initial pitch. Wolf's Final Smash is completely cloned however, being a Landmaster that is colored red, and functions identically, just having much greater power at the expense of less duration.
Wolf's physical attributes are also quite different from Fox's, being a rather heavy character, with great air speed that gives him superior mobility, unlike Fox and Falco.
Wolf ranks 14th on the current tier list, in C tier. Wolf is a borderline viable character, who has the tools to take on any character in the game, including Meta Knight, with his great mobility, fast and far reaching attacks, and a plethora of options. However, Wolf has a severe weakness to chain throws, including multiple zero-deaths, which leads to him being countered by a few character that can exploit this, most notoriously King Dedede.
A pilot whose real name is Wolf O'Donnell. He leads a group of mercenaries called Star Wolf. He's crossed paths with Fox many times, and each acknowledges the other as a competent rival. Wolf's constant interference with Fox is a result of Wolf's history with Fox's dad, James. Wolf's long history of criminal enterprise has resulted in a large bounty on his head.
Wolf is no longer playable; however, he does appear as a trophy in at least Super Smash Bros. for Nintendo 3DS. Fox also has a custom side special called "Fox Flash" that functions similarly to Wolf's Wolf Flash.