>A new trademark has been discovered as being registered by Nintendo, GameFreak and Creatures Inc. in Japan. This trademark is for デルタエメラルド Delta Emerald. In addition to this, in the US, at the same time as the Pokémon Omega Ruby & Alpha Sapphire domains were registered, one was registered for Pokémon Delta Emerald.

Remember that?
Well take a look at the carvings in the cave where we meet Steven. In both screenshots, there's a delta symbol, and obviously is meant to represent Rayquaza.

Delta/Primal Rayquaza confirmed?