Krystal is a one-off character from the Pokémon anime episode "As Clear as Crystal," voiced in Japanese by Makoto Tsumura.
She first meets Ash and the gang when Pikachu is exhausted from one of Team Rocket's botched theft attempts. Krystal knows about a hidden lake nearby—one with a mysterious crystal at its center—and offers to take them there so Pikachu can recover. The catch is that Ash has to swear he won't tell anyone where it is.
The lake turns out to be a natural healing spot for injured and tired Electric Pokémon from the surrounding area. Word gets out though, and Team Rocket predictably shows up trying to swipe the crystal. When they actually succeed in stealing it, a Zapdos arrives to stop them—but without the crystal's healing power, even the legendary bird ends up badly hurt and can't recover.
Ash manages to get the crystal back, and with help from Pikachu and the other Electric Pokémon around the lake, Zapdos fully heals. After everything settles down, Ash and the group say their goodbyes to Krystal, reaffirming their promise to keep the lake's location a secret.
Content compiled by AnimeList.moe from publicly available sources.
