The Hero might be introduced with a rival, or a rival might be introduced later, either starting that way or from a HeelFace Turn. Then there's one of their enemies, who decides to help the hero but without officially joining their group for whatever reason - usually it's when they're facing a common enemy (usually the Big Bad) or when they're facing the threat of the destruction of everything (in which case the Big Bad him/herself might team up with the hero). The enemy in this case might also join because he wants to be the one defeating/killing the hero in the end.
Sub-Trope of Power Trio. See also With a Friend and a Stranger, Ragtag Bunch of Misfits, Teeth-Clenched Teamwork, Friendly Enemy, Worthy Opponent and 11th-Hour Ranger (the villain is almost always this). Compare The Good, the Bad, and the Evil, which may overlap (in form of "The Good, The 2 Bads, and The Evil") but its focus is more on "Hero vs. Rival vs. Enemy" instead of the three working together.
- Dragon Ball
- Mostly seen in Dragon Ball Z and Super, Goku fights along with Piccolo and Vegeta, both were former enemies that made a HeelFace Turn but now battle together. The difference is that Piccolo is more a Friendly Rival towards Goku, while Vegeta starts off as an Anti-Villain who is forced to team up with the heroes as well as being a Stock Shōnen Rival, which is especially prominent in the Buu Saga where Vegeta takes the chance to be more powerful than Goku by turning back to evil.
- Also seen before in Dragon Ball, when Goku was just a child, with Yamcha and Tien Shinhan, also both having a HeelFace Turn and being part of Goku's group, but being more friendly than Piccolo and Vegeta. In this case it's downgraded, with Yamcha being more like a friend for Goku and Tien being more serious about his rivalry than Yamcha.
- Dragon Ball Super: By the Tournament of Power, Vegeta gets promoted to Friendly Rival while the Arch-Enemy spot gets filled by Frieza. The three of them end up in a Last Stand against Jiren after Android 17's attempted self-destruct puts him out of commission. It's particularly notable due to Vegeta becoming jealous that Goku is able to work better with Frieza than with Vegeta. This trio continues on into Dragon Ball Super: Broly.
- In Book 3 of Pokémon Adventures, Red has to team up with rival Pokémon trainer Blue and thief Green in order to get into Viridian City, which is apparently off-limits due to Team Rocket using a Psychic Pokémon to put a large bubble shield around the city, keeping Red, Blue, and Green from getting in.
- In Ranma ½, one of the main Power Trios is between Ranma and two of his main rivals Ryoga and Mousse. While Ryoga has cast aside most of his animosity and has forged a Bash Brothers dynamic with Ranma, Mousse on the other hand still remains very bitter towards Ranma and will only ever work with him for personal gain and usually with ulterior motives.
- The three most reliable duelists in Yu-Gi-Oh! that end up fighting alongside each other more and more as the series go by are Yugi (The Hero), Joey (The Lancer) and Kaiba (The Rival).
- Death Note has a very unusual example involving two Villain Protagonists and a Hero Antagonist. Light Yagami/Kira finds a rival Kira in the form of Misa Amane, who eventually tracks him down and teams up with him. However, both end up getting captured by L, Light's Arch-Enemy, to which Light pulls a Memory Gambit on both him and Misa to evade incrimination. With a new Kira out there, the now amnesiac Light and Misa join L and the rest of the "Kira Task Force" to hunt down the new supernatural Serial Killer.
- Lupin III:
- Lupin III: Episode 0: First Contact: Lupin III is trying to steal the Clam of Hermes, and finds himself working at cross purposes, as usual, with his friend Brad. He meets Jigen working as a guard for the mob boss who possesses the treasure. Although initially thwarted by Jigen, Lupin was able to find Brad's necklace, and he presents the memento of Brad's death to his girlfriend, Fujiko. Fujiko working with the mob and Lupin wants to make out with the treasure herself and is willing to sell Lupin out for the chance to do so. After another failed attempt to steal the Clam of Hermes, Lupin, Fujiko, and Jigen are all imprisoned by the mob boss. When Goemon shows up to take the Clam of Hermes for himself, the three prisoners turn the tables on the mob and break out.
- Lupin III: The Woman Called Fujiko Mine: "Blood-Soaked Triangle" has Lupin III competing with Jigen to get this week's treasure. He's trying to get an alexandrite peacock to prove to Fujiko that he's worthy of her. Once they're both far enough into the pyramid, Fujiko sets them against each other in one of the traps, completely uncaring who dies (if both died, it wouldn't bother her). Once they get past the trap, though, they learn that removing the peacock leaves them completely trapped, and have to work together to escape.
- The Castle of Cagliostro: Both Lupin III (with Jigen & Goemon) and Fujiko have gone to the titular castle to steal the counterfeiting plates of Count Cagliostro. Inspector Zenigata learns about Lupin's presence and enters the castle to arrest him. Both Lupin and Zenigata become temporarily trapped in the dungeon, so they work together to escape. Zenigata knows the Count is breaking international law, but his superiors inform him that the Count cannot be arrested because he has too many political connections. Later, Lupin convinces Fujiko to have Zenigata prepared to sneak into the castle, ready to chase after Lupin for stealing the Count's bride. In fact, Zenigata runs to the Count's counterfeiting operation with Fujiko following with a live worldwide broadcast to prove the Count's evildoing. At the end of the movie, Fujiko has stolen the counterfeiting plates, Lupin (with Jigen & Goemon) chases her to get a percentage of the heist, and Zenigata is chasing all of them to put them behind bars.
- Lupin III fights along with Jigen and Goemon, both were former enemies that made the HeelFace Turn and now they battle together. The difference is that Jigen is more a Friendly Rival for Lupin, while Goemon was more of an Anti-Villain who simply hasn't carried out his assasination yet.
- In Diablo: La Resistencianote , Diablo was trapped in a suburb with a Mob War between two hooligan gangs from rival soccer teamsnote . That, until demons sent by Vardan, The Dragon of Lord of Entropia, who go for human flesh, no matter in which the side they're on. To avoid a big massacre, Diablo has to team up with both gangs to stop the demons and as a third side, the religious people of the suburb who also stand against the demons as the gangs.
- Star Trek: Debt of Honor: The final fight against the extradimensional creatures sees Jim Kirk team up with his Klingon rival Commander Kor, and Romulan frenemy Commander T'Cel with whom he has Unresolved Sexual Tension (she had previously been a civilian consultant stationed on USS Farragut and escaped with him when it was destroyed, only to leave to draw off Romulans investigating the incident and turn out to be half-Romulan herself). Their bond of mutual respect is enough to overcome the Space Cold War state between their three governments so they can deal with the monsters that have been attacking area shipping for decades.
- Wonder Woman (1987): The climax of the "Challenge of Artemis" arc sees Diana team up with her rival Artemis and villain Circe to fight the White Magician. The team up is a bit odd as Artemis was already nearing the end of her fight with the Magician by the time Diana got there, and Circe initially refused to join (though she did send Diana along) and only arrived even later after Artemis' fate was sealed.
- In Ursula K. Le Guin's short story Vaster than Empires and More Slow, the crew of an intergalactic scientific expedition has to study a forest-planet where the "trees" form one sentient organism and slowly drive the crew to insanity/catatonia. The story ends with the three members of the crew left standing teaming up to put an end to the situation: open-minded, fair and placid coordinator Haito, the prickly and condescending but ultimately harmless sensor Osden and paranoid Blood Knight biologist Harfex. Fits this trope rather than The Good, the Bad, and the Evil because none of them are exactly evil: Harfex is fighting Sanity Slippage and only wants to kill The Empath Osden because the latter can't help but perceiving and mirroring the unconscious hostility of other crew members towards his deformity, endangering the mission and crew. The crew used to gang up together against Osden from the moment his behavior became too insulting to bear, but the moment Harfex tried to physically attack Osden, Haito made it clear that Osden's unpleasantness could be tolerated, but Harfex's violence was unacceptable and would have consequences. It's only after this supremely awkward moment that they have to team up.
- Kamen Rider Drive has the Rider trio of Shinnosuke, Chase, and Gou. Chase was actually a former enemy to both Shinnosuke and Gou but made a HeelFace Turn and acted like Shinnosuke's lancer while Gou acted hostile to Chase since he hated all Roidmudes. While Gou could work well with Shinnosuke who he like, it took facing the other Roidmudes and his evil Father Banno for him to work with Chase.
- In the Arrow Season 5 finale, Oliver is forced to recruit two of his past Arch Enemies, Malcolm Merlyn and Slade Wilson, to help take down the newest Big Bad Adrian Chase. Oliver still holds a huge grudge against Malcolm, despite having worked with him in the past. While Slade became an Evil Former Friend after getting hit with Sanity Slippage thanks to a Super Serum, but after regaining his rationality, he and Oliver become Bash Brothers once again.
- The penultimate episode of season one of Damnation sees Seth forming a temporary alliance with estranged half-brother Creeley and sworn enemy Connie in order to stop The Black Legion from taking over their town.
- Towards the end of season 3 of Queen of the South, Teresa and her on-again-off-again ally James team up with Teresa's mortal enemy Camila Vargas in order to fight General Cortez, who is an enemy to both Teresa and Camila.
- An inverted example happens in WWE when Daniel Bryan teams up with Kane (making the "Team Hell No!") and adding The Undertaker to the mixture to fight The Shield in 2013. In this case, Bryan is the contrary force of the team, but is more friendly than the "Brothers of Destruction" (Kane and Undertaker), also seems by many as The Hero of the team.
- The final part of BoxxyQuest: The Gathering Storm is a textbook example. The Greater-Scope Villain has been revived, and the only three people left to face it are Catie (the hero), Arianna (the rival), and Boxxyfan (the baddie). In Ariannas case it marks a genuine HeelFace Turn, but for Boxxyfan its merely a teeth-clenched Enemy Mine situation.
- EXTRAPOWER: Attack of Darkforce: The hero Zophy, his rival V, and Zophy's long-time opponent Blackberry join up with the heroes in defense of the Earth. Though it is clear that Blackberry will continue her ambition in resurrecting the ancient wizard Diamond Mine, and that Zophy will stop her when that day comes, the threat of Dark Force against the Earth is a more immediate concern.
- Mega Man has to team-up with his brother Proto Man and his nemesis Bass to fight together against Dr. Wily when Mega Man can't handle it alone. This "alliance" is seen first in Mega Man & Bass (with Proto Man falling over at the beginning) and later in both Mega Man Power games (in Fighters with Duo as the Stranger) and in Mega Man 10, with Mega Man and Proto Man battling together as brothers, and Bass making a truce to also stop Wily, who goes against his own plans.
- In the last story of Sonic Adventure 2, Sonic (The Hero), Knuckles (The Lancer) and Shadow (The Rival) infiltrate the core of Space Colony Ark together. Knuckles uses his incantation to control the Master Emerald, while Sonic and Shadow use the Chaos Emeralds to transform and fight the Final Boss.
- Seen in Super Mario RPG with Mario, Geno, and Bowser. Mario is obviously The Hero and Geno becomes The Lancer to help Mario to recover the Seven Star Pieces, stop the Smithy Gang and save the world. In the case of Bowser, Mario's Arch-Enemy has his castle stolen, so he has no other option than to ally Mario and company to get his domains back.