Rayquaza is a DragonFlying typeLegendaryPokémon introduced in Generation III. It is known as the 'Sky High Pokémon' and is a member of the weather trio along with Groudon and Kyogre.
How to Obtain
Go to Cinnabar Volcano and talk to the guy with red wings in the house at the very back. He will have a feeling that Route _____/ _____ City will have a rare Pokémon. That Pokémon can be Rayquaza,Cresselia or Manaphy.
Rayquaza can Mega Evolve into Mega Rayquaza. In Project: Pokemon however, Rayquaza won't have Mega Evolution implemented.