The March 2014 issue of CoroCoro has announced Charizard events for Japan. They will be available via a serial code that will be inside of next month's issue. Each serial code will be different, and no code may be used more than once.
Players with Pokémon X will receive a Charizard that is holding a Charizardite Y, which will allow them to Mega Evolve it into Mega Charizard Y. This Charizard will know the move Inferno. No other info about these Pokémon are known at this time.