>>57263560All legendary pairs/trios tend to have some connection to the themes of the region or the antagonist, and, well, Kanto is pretty scarce in themes. The only things I managed to find are "advancement in technology and trying to create artificial pokemon", things like Porygon, Ditto, and Mewtwo's existence, Bill's experiments, and even innocuous things like the "technology is amazing!" or something like that guy. So if they would be a central legendary group for Kanto, I think it would be based around this theme.
The Green legendary could be organic, the pokemon has existed since Kanto was a thing, perhaps created by the emotions of the people and pokemon of Kanto, and its legend has been the basis for Porygon when creating it. The Red legendary is artificial, originally a Porygon but was experimented on by Team Rocket in an attempt to create a powerful pokemon for them, mutating it into the legendary pokemon we see. And finally the Blue legendary, another artificial pokemon also sorta based on that original legendary of Kanto, but it's an ancient golem created to protect Kanto. For types, I would say Green is Fairy/Normal, Red is Steel/Dark, and Blue is Fairy/Steel.
