“Every story has a setting.”
—Split, Destroy the Godmodder 2
The Trifecta consisted of three universes: Universe A, Universe B, and Universe C. Universe A consisted of the entirety of Homestuck, including Alternia and Homestuck's Earth. Universe B consisted of Earth "Prime", and is mostly similar to Nonfiction Earth, barring several important changes. Universe C consists of Minecraftia, particularly GodCraft.
The nature of the Trifecta allowed its three universes to interact with each other in tandem, almost surpassing the need for Fourth Walls. This let a multitude of stable time loops and easy passage between one universe to another occur, resulting in events such as the Homestuck Invasion, the Arrival, and the Mate.
The Trifecta was ultimately destroyed in the End of Act 4/Act 5 of DTG2 when all three of its universes were destroyed at exactly the same time in a stunning event known as the Execution. Universe B was restored by Team Mojang, but the other two were permanently destroyed.