Foil / AIEchidna's Five Nights at Freddy's

• Freddy Fazbear has multiple:
  • One with Sparky the Dog. Freddy is a rampaging homicidal maniac with a endless bloodlust who would kill his teammates with no hesitation while Sparky is a Gentle Giant at heart, unable to harm a fly, all the while remaining loyal to his friends until the very ending.
  • One with Michael Afton. Michael had killed his brother by accident and, flooded with guilt, decided to turn his life around. Freddy himself, as revealed in Beginnings, had a similar accident, killing a night guard. However, instead of feeling remorse, Freddy gains a satisfaction of bloodlust and begins to murder innocent night guards for his own enjoyment.
• Nightmare to Fredbear. Nightmare is a sadistic Grim Reaper who, while taking souls who have only cheated death unfairly or who are close to dying, either stalks them in their last moments or, in the case of cheaters (or sometimes out of spite), plays a sadistic game with them. Fredbear, meanwhile, is a polite fellow who gladly guides Michael through and tries to help him out of the situation Nightmare had placed him in. (Word of God states that like how Nightmare is Death, Fredbear (albiet assumedly not the real one) is considered to be Life.)
• Bonnie the Bunny to Chica the Chicken. Bonnie can barely muster up any courage to speak to Freddy, much less talk back to him, only being able to respond with whimpers and whines. Chica, on the other hand, is able to do so much as be sarcastic to Freddy and get away with it. The fact they're implied to be in love with each other only makes this cuter.
• To a much lesser extent, Foxy the Pirate Fox and Mangle. Foxy is brutish, introverted and easily prone to anger. Mangle, however, is carefree and extroverted, thus she likes to tease Foxy. While Foxy completely hates it at first, she begins to grow on him near the end.
• Michael Afton and Jeremy Fitzgerald could qualify as this. Michael returns to the various pizzerias under various guises in order to stop Freddy and his plans. Jeremy went to the pizzeria once, unaware of what was going on, and was murdered.