Penelope (Sly Cooper)

In the Sly Cooper series, a Dutch mouse named Penelope became an invaluable ally to the Cooper Gang during their stint in Holland. Initially an enemy under the guise of the Black Baron,

Sly 3: Honor Among Thieves
In the third chapter Flights of Fancy, Penelope is introduced as an RC expert contacted by Bentley via email exchanges. She promises to aid them in the game's final heist against Dr. M if they assist her in helping her employer The Black Baron during the upcoming ACES dog-fighting tournament. Sly and the gang assist her and partake in the ACES championship while undermining recurring rogue Muggshot with the (unknowing) assistance of Carmelita Montoya Fox. However, during the final competition, Sly shoots The Black Baron's plane down, forcing him to leap atop a plane's left wing. Sly pursues and the two fight, with The Black Baron being revealed to be none other than Penelope in disguise when Sly wins. She reveals that she posed as The Black Baron in order to bypass age restriction laws in the ACES tournament.

Throughout the rest of Honor Among Thieves, Penelope becomes an ally with her RC car skills and develops an attraction to Sly despite Bentley's obvious attraction to her. However, during their time in Blood Bath Bay, she starts to reciprocate Bentley's feelings

Sly 4: Thieves in Time
In the intro, Penelope is mentioned to have worked alongside Bentley on constructing the time machine. However, at some point, she mysteriously vanished around the same time the Thievius Raccoonus started losing its records due to tampering by Le Paradox's desire to collect all Cooper ancestor artifacts. Her disappearance, along with the altered text, prompt Bentley to reorganize the Cooper Gang to find her.

During the fourth level Of Mice and Mechs, Sly's ancestor Sir Galleth is defeated and humiliated by a rogue called The Black Knight, an anachronistic suit of robotic armor, working on behalf of Le Paradox. As the Cooper Gang foil The Black Knight's operations, Bentley discovers to his horror that is in fact Penelope acting as The Black Knight. She escapes to a larger mech and does battle with Sly, attempting to kill him with missiles and shockwaves while he retaliates with arrows that damage her robotic armor's weak spots. However, in the process, Sly becomes trapped under some rubble, seemingly giving Penelope the chance to kill him.

She is interrupted by Bentley who counters her in a mech of his own and asks why she would betray them. Penelope argues that she did it for Bentley's sake, as working for/with Sly was only holding back his true potential. Working for Le Paradox, Penelope arranged the Black Knight plot as a means to get Le Paradox's help so as to kill Sly. Naturally, Bentley only rejects her "help" and does battle with her, scoring a victory and saving Sly from her.

Attributes
In both games, Penelope shows a mechanical knack as evident by her Black Baron and Black Knight costumes.