The creation trio is a fan term used to refer to three powerful Legendary Pokémon of the Sinnoh region: Dialga, Palkia, and Giratina. Other fan terms include deity trio and dragon trio. According to Sinnoh myths, they were created by Arceus simultaneously when the universe began.
Much like members of other Legendary trios, the three Pokémon have similar appearances. Each has Dragon as their secondary type, as well as a base stat total of 680, divided among the stats as 150-120-120-100-100-90, in different orders.
Each of the members of this trio, including its trio master Arceus, have control over their own dimensions. Dialga controls time and Palkia controls space, two aspects of the four-dimensional universe that the Pokémon world, like our own, is a part of. Giratina has control over antimatter and the Distortion World, where time does not flow and space is unstable, while Arceus has its own world where the Hall of Origin is located.
The three members of this trio share the Ability Pressure, as well as the Hidden Ability Telepathy; however, Giratina's Origin Forme has Levitate. Likewise, the three are the version mascots of the three Generation IV Sinnoh-based games, and have similar level-up learnsets.
The creation trio makes another appearance in Pokémon HeartGold and SoulSilver. An event involving Cynthia and Arceus at the Sinjoh Ruins will allow a single one of the three to be obtained at level 1.
This is what i got in bulbapedia.