In Path of Radiance, Mia is a mercenary hired by Crimea, and is captured by Daein soldiers. As a result of being set free by Greil, she joins his mercenary band to pay off her debt, but remained with the mercenaries. Mia's training tends to be rather extreme, with her attempts to spar with Ike being rather aggressive in nature, whereupon she convinces Rhys to stand by the side in order to heal any wounds she may receive. She is most likely Ike's preferred sparring partner, as she tends to not complain about the fact that he never holds back during their training sessions, even seeming to enjoy them. After the defeat of Ashera, Mia sets off on a journey around Tellius in search of new opponents, occasionally stopping by Greil's retreat to rest.
Mia can be described as being eccentric and upbeat. This may be observed in her support conversations, where she will often run around and challenge the first person she sights to duels. After learning that her "archrival [will] [ride] towards [her] in white robes", Mia takes this to mean that Rhys will someday gain power to rival her own, despite the fact that Rhys is nothing more than a humble Priest with no fighting capabilities. Despite her eccentricities however, she is a genuinely nice girl, as shown during one of her training sessions with Rhys, in which she forbids him to practice with swords anymore because it was making him sick.
Through her support conversations with Largo, Mia is observed to be strongly against the traditional stereotype of women not being able to fight. She is thus quick to accuse male opponents of going easy on her or assuming that her prowess as a swords-woman is inferior due to her gender.
Mia is a well-balanced unit, with her only flaw being that of her low HP, an issue that can be easily fixed with a Seraph Robe. Her Strength growth may be a little unstable, whereupon a support with characters such as Rhys may come in handy. Her unnaturally high resistance can help her fight magic units and being able to always attack first can possibly prevent her from taking more damage that she'd be able to.
Mia's Strength and Defense growths are well balanced in Radiant Dawn, with her high Speed and Luck making it hard for opponents to successfully land any blows on her. She is most likely to cap all her stats except Magic and Resistance, although her Defense and Strength caps may be rather disappointing. Mia also possesses excellent Bonus Experience potential, as her Skill and speed are nearly capped when she joins the player's army. While she may have issues finishing off foes without Killer weapons or the Astra skill, Mia's high Skill allows her to activate skills quite frequently, allowing her to spontaneously destroy foes.
Throughout the Tellius series, Mia searches for her rival "clad in white", accusing several unlikely characters of being this person. Strangely enough she never seems to take notice of Lucia, who serves in the same army as her in both games and is a Swordmaster in white garb.
If Mia supports Ike in Radiant Dawn, she will refer to him as "boss" instead of Ike.