Maria is the Gym Leader of Nowtoch City's Gym. She specializes in Normal-type Pokémon and gives the Normal Badge to Trainers who defeat her.
In the game
Maria appears in Pokémon Uranium as the Gym Leader of Nowtoch City's Gym. This Gym is the first to be challenged by the player. Trainers who defeat Maria will receive the Normal Badge, along with TM27 (Return).
When you first enter the city, the door to the gym will be blocked. Instead, you'll find a fan of Maria's, as she was the former Champion of Tandor. He give Maria's house key and ask you to go to her house southeast of the city, just north of the park. Once you enter, Maria will race over to the gym and you can proceed to challenge her.