Sami is a CO from one of the four countries that comprises the Allied Nations, Orange Star. She is one of the first CO's played in the games, debuting in the eighth mission of Advance Wars.
Sami is pretty calm and lively most of the time, sporting a somewhat "happy-go-lucky" atitude, similar to Andy. However, she is not one to be crossed with, and can easily get angry in the right situation. This is best shown when fighting Sonja in Advance Wars, where she almost goes berserk on Andy for being tricked so easily. She's also outspoken and doesn't hesitate to be rude when angry, as shown in Advance Wars 2, where she is cornered by Adder, who tries talking her into surrendering. Her response is shown to be quite "inapropriate", to the point that one of Green Earth's soldiers doesn't feel "comfortable" reading it out loud, and Eagle starts laughing upon reading it. Sami also seems to be a bit of a suck up to her superiors (specifically Nell), as noted by Andy. Despite all this, she is shown to be caring of those close to her, like in Advance Wars when she refuses to leave Eagle behind to fend off Sturm's forces, or in her talk with Eagle before the final mission of Advance Wars: Dual Strike, where she refuses to accept Eagle's promise in the case he dies, stating that making a promise like that means one of them will most certainly die.