Key Stone/Manga/XY

was given a Mega Ring with a Key Stone inside from Gurkinn as a child. With it, he can Mega Evolve his Li'l Kanga, Salamè, Élec,, and , into , Mega Charizard X, Mega Manectric, Mega Gengar, and Mega Pinsir, respectively.

Those taught by Gurkinn, the Mega Evolution guru, tend to use Mega Gloves. This includes Korrina, three unnamed students, and Gurkinn himself. Gurkinn stated that he gave Key Stones to 16 people through a Mega Evolution successor ceremony, with X being the sole exception. He later gave his Key Stone to, thus making her a successor as well.

At Lysandre Café in Lumiose City, Diantha shields Y and her friends from Lysandre's Pokémon by using her Mega Charm to Mega Evolve her into Mega Gardevoir.

Lysandre later obtains a Mega Ring from Malva outfitted with a Key Stone stolen from Korrina.

At the Lost Hotel, is made a Mega Evolution successor by Gurkinn. She is given a Mega Ring outfitted with the Key Stone from Gurkinn's Mega Glove. With it, she can Mega Evolve her into Mega Absol.

is later revealed to be a successor as well, keeping his Key Stone on a ring. When not in use, Blue wears the ring around his neck as a pendant. With it, he can Mega Evolve his into Mega Charizard Y.

Blaine later appears at the Pokémon Village, revealed to have reunited with. He had gained a Key Stone sometime prior and placed it in his cane, using it to Mega Evolve Mewtwo into either Mega Mewtwo Y or Mega Mewtwo X.