Erma has the power to turn invisible, something that is based on real-life Ermines' natural ability to change their fur coat. She uses this ability to sneak up on enemies an attack them by surprise, something that Sonic compared to Espio's own ability.

She is a mobian ermine and a member of the Arctic Freedom Fighters, and is notably aggressive in nature. While others of the team wanted to deal with threats to their homeland peacefully, Erma was eager to fight from the beginning.