Crisis Crossover / Video Games

• The King of Fighters series of fighting games is a Crisis Crossover for SNK, featuring characters from Art of Fighting, Fatal Fury, Ikari Warriors and Psycho Soldier, as well as creating several characters exclusive to the series (Iori Yagami, Kyo Kusanagi, and Rugal Bernstein being the most notable).
• Super Smash Bros.:
  • Super Smash Bros. Brawl has the story of Subspace Emissary. It involves all of Nintendo's major heroes (and a couple of others) teaming up to stop the titular Subspace Emissary from destroying the Smash Bros. universe. However, unlike the typical Crisis Crossover, this explicitly takes place in an Alternate Continuity where the characters are all trophies that come to life and fight.
  • Super Smash Bros. Ultimate brings together every single Smash Bros. fighter ever, plus a few new ones (with even more joining the fray later on), to take down the "ultimate enemy" named Galeem and his just-as-evil counterpart Dharkon in World of Light.
• EXTRAPOWER: Attack of Darkforce is technically this for the EXTRAPOWER series, despite being the first game released. Characters created over the course of Lucky Lamp Project's members lives unite together to face the threat of Dark Force's universal conquest. Later games would release these teams to their own stories and settings.
• Dissidia Final Fantasy has the evil god Chaos revive villains from Final Fantasy through Final Fantasy X in an attempt to sieze the Crystals and change history. Chaos' opposite number, the goddess Cosmos, calls on the heroes from the same games to unite and save the universe.
• Gundam Vs. Gundam NEXT has the Devil Gundam come to life and take over arcade games representing the entire Gundam franchise from the original series through Gundam 00, forcing the characters to team up to deal with the threat.
• .hack//Link is going this way, as characters from both of the "revisions" of The World are in it. (Tokkio's first two party members are Tsukasa from SIGN and Haseo from G.U., for example.)
• The Nicktoons Unite! series serve as this for Nickelodeon, with SpongeBob SquarePants, Danny Phantom, Jimmy Neutron and one or two other universes deal with a multiuniversal threat, differing each game.
• Nickelodeon All-Star Brawl 2 features a single-player mode where the main fighter cast and other characters and elements from their shows fight enemies in a roguelike campaign to stop Danny Phantom villain "Vlad Plasmius" from taking over the minds and worlds of the Nicktoons multiverse.
• Cartoon Network has the MMORPG FusionFall, though its art style makes it clear it is an Alternate Universe.
• Similiary to the Kamen Rider Decade example above, ASCII Media Works celebrated the 15th anniversary of their Dengeki Bunko imprint of Light Novels with the Nintendo DS RPG Dengeki Gakuen RPG: Cross of Venus, where an evil organization is attempting to derail the storylines of eight of their series and so your not-so-nameless protagonist and Shana must form a rag-tag group with their worlds' heroines to save their printed existences.
• Inverted in Poker Night at the Inventory, where Strong Bad, Max, The Heavy, and Tycho (from Homestar Runner, Sam & Max: Freelance Police, Team Fortress 2, and Penny Arcade respectively) team up to play poker. The sequel has Brock Samson, CL4P-TR4P, Ash Williams, Sam, and GLaDOS (from The Venture Bros., Borderlands, Evil Dead, Sam & Max: Freelance Police, and Portal, respectively.)
• The Marvel vs. Capcom series is this for both Marvel and Capcom.
  • The original Marvel vs. Capcom: Clash of the Superheroes reused the plot of the Onslaught saga and adding in Capcom characters.
  • Marvel vs. Capcom 2 has a more straightforward plot where Ruby Heart was gathering characters from both companies to deal with Abyss.
  • Marvel vs. Capcom 3 has Wesker and Doctor Doom team up, crossing over the Marvel and Capcom universes, and awakening Galactus in the process.
  • Marvel vs. Capcom: Infinite has Death and Jedah Dohma intend to fuse the two worlds together, result in a fusion of Ultron and Sigma with 2 of the Infinity Stones seek to dominate all life.
• The Suikoden series is headed this direction nowadays, but with original characters in an attempted re-invention. Suikoden Tierkreis introduced the multiverse concept and the next game is said to be focused around this.
• Resident Evil 6 is this for the Resident Evil franchise. Including Leon Kennedy, Chris Redfield, Ada Wong, and even the returned Sherry Birkin and a son of Albert Wesker, all face off against a new, global bioterrorism threat, rather than confined to certain locations to chase down a singular threat.
• EndWar is one of these for the Tom Clancy game verse, including former members of the Ghost Recon and Rainbow, along with the H.A.W.X. squadron and Third Echelon.
• Magical Girl Lyrical Nanoha A's Portable: The Gears of Destiny, which featured an unstable Humanoid Abomination whose out of control powers dragged in characters across time and space and produced Virtual Ghosts of dead people, incidentally allowing characters from the various recent installations of the franchise at the time (The Movie First, Vivid, and Force) to join in the fray against the new threat.
• As part of Artix Entertainment's 10th anniversary celebration, six of their active online games at the time (AdventureQuest, DragonFable, MechQuest, AdventureQuest Worlds, EpicDuel, and HeroSmash) were attacked by Chairman Platinum and his company, EbilCorp, sparking a cooperative war in which the playerbases of all six games had to band together as one and eliminate the invading forces in every single game within a week. The players won.
  • Prior to this, there was a St. Patrick's Day event (known in game as the Blarney War or Lucky War in-universe) that united the AdventureQuest, DragonFable, and MechQuest timelines in a successive war, and a war against Shearhide that was a crossover between AdventureQuest and WarpForce.
• Bringing the tradition into video games, Mortal Kombat vs. DC Universe has a plot along these lines with Darkseid being somehow and involuntarily merged (for the third time), now with Shao Kahn into an Humanoid Abomination who grinds the two universes into destruction just by existing. Midway considers it an Elseworld for the DC side of the story, though they did write the Kombat side so as to implicitly fit in between Mortal Kombat 3 and Mortal Kombat 4 (as well as hand it a Continuity Nod in Mortal Kombat 9: the Training Mode description for Shang Tsung's M-rated Captain Ersatz version of The Joker's gun fatality is "Shang Tsung has picked up a few tricks from previous opponents."). In real life, the crossover had the effect of Warner Bros., DC's parent company, being allowed to acquire Midway's Mortal Kombat division (now named Netherrealm Studios) when Midway went bankrupt.
• Though Jump Super Stars and its sequel have an Excuse Plot, it still does amount to Dr. Mashirito from Doctor Slump stirring up trouble, while the J-Heroes/Heroines try to stop him.
• What could possibly be powerful enough that all of the numbered Shin Megami Tensei protagonists, each of which powerful enough to fight against YHVH Himself, would have to team up with Nanashi, who actually does kill Him? Of course none other than Stephen, establishing his position as All-Powerful Bystander once and for all with a boss fight that is essentially YHVH on steroids.
• The crossover event Accel World vs Sword Art Online: Millennium Twilight, involves the Accel World and Sword Art Online characters being brought together and being forced to team-up against the threat that transcends time, Persona Vabel.
• Fate/Grand Order features nearly every Servant, and many non-Servant characters (some now summonable as Servants), from Fate/stay night, Fate/Zero, Fate/EXTRA, Fate/Apocrypha, and even Fate/Prototype and Fate/kaleid liner PRISMA☆ILLYA, in a storyline where the Chaldea Security Organization must fix time anomalies that could destroy the world. There are even characters from non-Fate works such as The Garden of Sinners.
• The Detectives United series is this for three of the Elephant Games mystery game series (Haunted Hotel, Mystery Trackers, and Grim Tales), with the three player characters coming together to combat supernatural forces that even their individual Occult Detective skills would not be able to overcome.
• Magia Record brings in all notable magical girls from the entire Puella Magi Madoka Magica franchise, including Kazumi Magica, Oriko Magica, Tart Magica, and Suzune Magica. In addition to a rather large cast of new characters. Most spinoff characters only appear in side-stories (within the game) and are not directly involved in the main storyline, but they all interact with Magia Record's main cast in some way.
• Worlds Align is this for AMAX Interactive. It posits that their games each take place in separate dimensions, which are connected, and the heroes of each series are "Watchers" who protect their worlds. When a great evil threatens the worlds of Dark Tales, Puppetshow, and Haunted Halls, they reach out to another Watcher - the player, who has been appointed to this role for the "real world." You actually play the games as yourself, assisting characters in ending the crisis, with No Fourth Wall keeping the characters from acknowledging that you're a real person who knows them from games.

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