The Wolfen was manufactured by Andross to counter the Arwing and prevent the Star Fox team from reaching Venom. With greater offense capabilities, but worse defense, the Wolfen fighters were designed to quickly dispose of anyone who got in Andross' way. Prior to their creation, Andross's ships were significantly worse than the Arwing, thus motivating their development.
The Wolfen first appears in Star Fox 64 in the 3rd mission of the game on the planet Fortuna, when the Star Fox team arrive there to stop its base from self-destructing. They are suddenly stopped by Wolf and his Star Wolf team, each piloting their own ship. The ships reappear alongside the evil team in a few other missions. During Star Fox: Assault, each member of Star Wolf upgraded their Wolfen to suit their own preferences with only Wolf keeping his ship similar to how it was before the Aparoid Invasion. During Star Fox Command, Star Wolf further upgraded their ships. Wolf maintained his traditional Wolfen, while Leon and Panther changed theirs to fit their preferences.
The Wolfen occasionally flies by in the background of Sector Z, but does not attack the player.
A Wolfen appears in the Corneria and Venom stages, occasionally firing lasers at the characters on-screen. The Wolfen doesn't target any character in particular. In the Corneria stage, once it has stopped firing, the Wolfen will then fly off the screen after a few seconds. If a character remains on it when it flies off the screen, that character will receive a Star KO. It also appears in the opening movie, piloted by Wolf as he makes his cameo.
The Wolfen trophy is obtained by clearing Adventure Mode in under 18 minutes 20 seconds or less.
The Wolfen reappears in the Corneria stage as it did before and also makes an appearance in the Lylat Cruise stage. It appears briefly in both Wolf's on-screen appearance in which he ejects from it to enter on the battlefield, as well as a bonus scene of the Subspace Emissary, in which Wolf ejects from the Wolfen and lands on the Lylat Cruise to face off the player. It's also notable that the Wolfen appears slightly different than the Star Fox: Assault version, where its wings are spread farther apart. The Wolfen also appears as a sticker in Brawl.
A class of starfighter piloted by Team Star Fox's rivals, team Star Wolf. Wolfen's boast more gravity-suppressing plates than Arwings, making their performance equal or perhaps even superior. When Team Star Wolf reappeared, they were piloting Wolfen II ships--improved versions with two laser cannons rather than one and capable of reflecting attacks by rolling.
The Wolfen appear as a distinct trophy. Also, the Wolfen reappears in the Corneria stage.
The Wolfen appears as a distinct trophy. Its Assault version is an item in Smash Tour: when used, it makes a selected opponent start the battle with 100% damage. Also, the Wolfen reappears in the Lylat Cruise stage.
Wolf returns as a playable character in Ultimate, and once again his on-screen appearance involves jumping out of his Wolfen. His new Final Smash, Team Star Wolf, involves him and the rest of Star Wolf firing on opponents from their Wolfens. The Wolfen also reappears on the three returning Star Fox stages in Ultimate.