UPDATE: CoroCoro has leaked with pictures and more information. Magiana was made 500 years ago by someone. It is is the Man-made Pokémon. It will be in the upcoming film and has some relation to Volcanion, possibly made to protect people from it. Full title of the upcoming movie is Volcanion and the Mechanical Magiana. To clarify, its typing has not yet been revealed.
UPDATE 2: Magiana’s body holds a mechanic that serves a function and only Volcanion who is chasing Magiana knows the mystery behind it. Volcanion is on a mission to return Magiana to the mechanical Kingdom of Azoth, where it has been kidnapped from. Presumably Magiana has some link to Project Azoth mentioned in ORAS.