ORAS Mega Rayquaza officially revealed!

[Pokemon Trainer]

During todays livestream, Mega Rayquaza was officially revealed along with its new ability and move and the official website was updated with the new informations.

Mega Rayquaza is said to achieve Mega Evolution in a unique way—unlike that of other Pokémon—due to its unique biology, so it won't have a Primal Reversion; this will be explained during the story.
Its type will remain the same: Dragon/Flying and will have a new ability called Delta Stream. When Mega Rayquaza whips up strong winds with its Delta Stream Ability, this is what happens:
・The moves Rain Dance, Sunny Day, Sandstorm, and Hail will fail.
・The Abilities Drizzle, Drought, Sand Stream, and Snow Warning will fail to activate.
・Moves of a type that Flying-type Pokémon are usually weak to will only deal normal damage to any Flying-type Pokémon in the battle.
Also, with Delta Stream, weather effects last indefinitely as long as Mega Rayquaza remains in battle. When it is swapped out for another Pokémon on your team, the weather immediately returns to normal.
This is different than the Abilities Drizzle, Drought, Sand Stream, and Snow Warning, which can all affect the weather for five turns after being activated in battle, regardless of whether the Pokémon with these Abilities are still in battle or not.
The Delta Stream Ability and the Air Lock Ability are different in that Delta Stream fills the air with strong winds for as long as Mega Rayquaza remains in battle. Air Lock cancels out all weather-condition effects for all of the Pokémon in a battle as long as Rayquaza remains in the battle.

The new move is called Dragon Ascent, which Rayquaza alone can use, is a powerful one. It boasts one of the greatest power ratings of all Flying-type moves, putting it at the top of its class. Not only will you be surprised by its overwhelming power—you'll be mesmerized by its majestic appearance! After soaring up toward the heavens in a great burst of speed, it crashes down in attack, dealing massive damage.

The official website added some lore behind Primal Groudon, Primal Kyogre and Mega Rayquaza.

It was a primal age, early in the world's history... The natural world was overflowing with energy. That energy granted Groudon and Kyogre an overwhelming power. Seeking ever more of that energy for themselves, the two clashed again and again, and their battles cast the people and Pokémon of Hoenn into great danger. Brimming with the overwhelming power granted by the energy of nature, this transformation was named by later people "Primal Reversion." And the people called their tormentors Primal Groudon and Primal Kyogre.


One Pokémon looked down upon this battle from the sky above. The Pokémon that dances in the heavens: Rayquaza. Rayquaza is venerated by the people of Hoenn as their protector and savior. When Primal Groudon and Primal Kyogre had battled for 20 dawns and 20 nights, the world began to lose its natural balance and tilt toward destruction. The people, unable to endure any more, cried out to their mighty savior Rayquaza before a great stone that shone with rainbow brilliance. And a change came upon Rayquaza, weaving in the sky above Primal Groudon and Primal Kyogre. Suffused in brilliant light, its body began to transform visibly. And then...