Gaia is a mentioned world of the blog, although it'll likely be more prevalent soon. It's a world where Mega Evolution never existed (ex. Ruby and Sapphire instead of OmegaRuby and AlphaSapphire). Mega Evolution doesn't work in the world and is incompatible in the blog. Those who come from this world are also incapable of performing Mega Evolution.
This follows the canon of the main games up until Generation V. Kalos and the other regions do exist; however, they have not undergone the events of their associated games.
Heidi lived in this world for 1,000 years. She was transported here from Ruined Kingdom until soon after Elysium's events of Sun and Moon. The Ultra Wormholes that were summoned from the Aether Incident caused her and Lauren to be sucked out of Gaia and into Elysium, which is why they live in Elysium to this day.
The world no longer has humans*. A year after Heidi and Lauren disappeared, Friede commanded Morrigan, the Arceus of the world, to destroy all of humanity. Morrigan agreed and kicked off a civil war between the Legendary Pokémon in her world that wanted to save the humans and those that did not. Those that wanted to save the humans all lost and were killed alongside the humans that they tried to protect.
Pokémon from this world have the normal catch rate.