Mary was a young girl from Mallet Town in the Pokémon Universe, a Pokémon trainer. She had a rivalry with Gash Ketchum since early childhood. Her starting Pokémon was Krypton Firefly.
History[]
Journey with Gash[]
When Gash left the town on his journey to become a trainer, she confronted him and challenged him. He defeated her Firefly with his Creeper; after that, he convinced her to travel with him.
Throughout the journey, she acted as his conscience, in her own faux-bullying way. She would often stop Gash from doing anything she considered wrong. ("Pokémon Stop")
Cracks in the Universe[]
When Gash stole a Seed from Prof. Ginkgo's office, Mary tried to stop him from battling Ian -- to no avail. In the ensuing adventure, the Universe began to form cracks and Umbrians poured out of them. Mary journeyed with some of Ian's companions, trying to catch Gash and Ian and fix the Universe.
During this journey, Rui, Ian's sister, became infatuated with her and flirted with her very blatantly. Mary didn't seem interested, and ultimately said so, though she did say the two made a good team and gave her a kiss on the cheek. (Pokémon Tales story: "Seed of Reality")
Three Keys[]

Mary, at her desk, falling asleep while reading and websurfing.
One day, Mary fell asleep while reading a book and surfing the web at the same time. She had a strange vision -- she was in a strange place with a Pokémon Center with no windows. She caught a Pikachu, which offered no resistance. Inside the center she had a battle -- but her Pikachu didn't fight for her. Instead it, and the enemy Pokémon, both turned to stare at her. Then she saw a vision of the world, with three keys emanating from it -- Digital, Devised, and Dream. Then she woke up. ("Pokémon Stop: KEYS")
Behind the Screens[]
- Mary is inspired by Gary, Ash's rival from Pokémon. However she's a separate character, merely filling a similar archetype.