In order to Mega Evolve, most Pokémon must be holding their appropriate Mega Stone and the Trainer must have a Key Stone. The Mega Evolution sigil, as seen in Pokémon Tretta Professor Sycamore theorizes that Mega Evolution can only be achieved if there is a strong bond between a Trainer and the Pokémon. However, according to Zinnia's grandmother in Pokémon Omega Ruby and Alpha Sapphire, Rayquaza was the first Pokémon to Mega Evolve Mega Evolution was first discovered by the first meeting of humanity and Rayquaza. According to a Kalos legend, the first Pokémon to have been Mega Evolved was a Lucario. The Tower of Mastery is also related to Mega Evolution. Korrina, the Gym Leader of Shalour City, is said to know secrets about Mega Evolution.
