Kris

Kris is the female playable character in Pokémon Crystal. Her male counterpart is Ethan. She was the first female player character in the core series games, a feature that would be carried on in subsequent game releases. As she only appears in Pokémon Crystal, she has the fewest appearances by a player character in the core series. In Pokémon HeartGold and SoulSilver, she is replaced by Lyra. (Source: Bulbapedia)