Greta

She is one of the 7 Battle Frontier Aces, a very strong fighter with great determination; she is the fourth Ace you face in Pokémon Emerald.

Greta is a slender girl of average height. She has short blonde hair styled in a bob with bangs and large blue eyes. She is wearing a sky-blue lycra jumpsuit under her coat, which is short and black with cherry-pink edges. She is wearing cherry-pink sneakers with white toes and white laces.

Despite being only 15 years old, her personality is very determined and strong.

She is such a prodigy that she is the fourth brain of the frontier in the Hoenn region. She is in charge of the battle arena at her young age.

Heracross, Umbreon, Shedinja, Umbreon, Gengar, Breloom

It's from the Pokémon universe, specifically the Hoenn region, and is part of the Frontier Brain.

She is the trainer of Chuck/Aníbal and Brawly/Marcial, 2 Pokémon Gym Leaders.

It is the fourth in the battlefront, with Sabino being the first, Tactio the third, Fortunia the second, Aniceto the fifth, Destra the sixth, Valente the ninth, and Jericor being the leader.

At 15 years old, she's a prodigy in Pokémon battles, and is as mature as an adult woman.