>>48797892Because the games and anime are one in the same now (but also not but who cares), Mewtwo is now openly stated to be created by Team Rocket.
Even the lowest of the gang's grunts know of Mewtwo and blab about it constantly starting from your first encounters with them in Mt. Moon, but somehow neither authorities nor veteran trainers can figure out what the fuck they meant by this.
When you first enter the Celadon Hideout, they're harboring Mewtwo in there for some reason and you, being the Chosen One Special Snowflake, resonate a special energy of friendship with your Pokemon that Mewtwo senses, gradually breaking it from its restraints until it frees itself and goes fully rogue after you defeat Giovanni. Mewtwo shittalks Giovanni and says some cryptic shit to (You) before fucking off, and Giovanni wonders what's so special about (You) for his greatest creation to take interest like that.
Future Team Rocket meddling features similar scenarios of Mewtwo showing up or being alluded to, but the story takes a turn at Silph Co when Giovanni finally realizes your Power of Friendship and catches you off guard in an attempt to kidnap you and make you into a perfect subordinate, only for Mewtwo to show up and rescue you. You get more cryptic shit hinting towards the Pokemon Mansion, wherein you then get a mandatory revised loredump about Mew and Mewtwo that's heavily based on the anime, and Mew's there for some reason and it joins your party willingly because it senses your pure heart and desire to help Mewtwo come to terms with the conflicting feelings it has about humanity.
Giovanni has Archer act as the Viridian Gym Leader this time around, and you're required to go to Cerulean Cave before you can tackle the Pokemon League for the climatic showdown with Giovanni, but not before you battle Mewtwo as it demands to see what good you and your Pokemon's bonds stand against the "ultimate fighter", and when you win, it learns the error of its ways and joins willingly.