Marta lost her mother during the Giant Kharlan Tree's rampage. She tends to think in right-and-wrong terms. She is a bit of a tomboy, so she is passionate about getting her way.

On the left side of her forehead is the Ratatosk Core, which is imprisoned in a dormant state. Emil becomes her guardian in order to protect her and the Core. She views Emil as effeminate, but believes that he possesses a hidden strength.

She wears a keychain that resembles Mieu from Tales of the Abyss, as well as a pouch on her back that resembles Tokunaga from the same game.