A interdimensional naked dood goes around with bugs made of darkness and triggers bombs that create pocket dimensions and swallows them up which causes a gigantic heavenly goddess thingy to summon Glovers to fire lazerbeams at everyone to blink them out of existence only for a lone director favorite to release these blinked sus imposters and recruit an army of spiritual denizens to fight against this heavenly goddess only for its dark brother to come in and crash the party leading to multiple endings.
Instead of an evil entity bringing together these worlds, one original world unaffiliated with the rest is on the bring of collapse and ruin thanks to a scourge of some kind...could be zombies, could be robots, aliens, who knows. We can decide later. In order to save their home, the Queen Elizabeth of the World uses the last of her magic to summon heroes and heroines from various worlds, timelines, and universes to fight against this threat. While to some, they would rather go back home rather than fight someone else's fight, they start to learn that there is a chance that is blight could extend beyond this world's borders and into their own as it can jump multiverse boundaries. Combined with the threat of their own universes and the plight of the innocents in this world, the decide to face this threat together.
However, it is revealed that the Queen of the World is also the Dark Queen of the World DUN DUN DUN, a malevolent force who, when the Queen used the life force from her body to summon the heroes, managed to take over the body and alter the spell to also bring in the villains and monsters from this world and to anchor the worlds to this world to allow the this scourge to spread over the multiverse of madness. Eventually, it is revealed that both the Queen and Dark Queen were working in tandem to bring about a cataclysmic event that would engulf the entire multiverse resulting all these universes vanishing from existence. This energy we would be rerouted by both queens to recreate this original world but as THE original world and the center of the multiverse with both as Queen of the Multiverse....
So yeah, a dark entity brings in heroes from multiples worlds...
I call it Capcom X Namco 3 + SNK: A Good Entity Brings in Heroes to Fight but Ends up Being a Dark Entity