
Although the literal translation - "deadly female" - may adequately describe our gun weiling first liuetenant, she does not fit within the defined stereotype itself:
femme fa·tale n.
1. A woman of great seductive charm who leads men into compromising or dangerous situations.
2. An alluring, mysterious woman.
Such examples of this, stemming back as far as the Sirens of The Odessey and even Eve from Genisis, can be found littered throughout modern day manga. Fumiko from Lupin III and Faye from Cowboy Bebop are two such clear cut examples of the Femme Fatale. These ladies are deadly, yes, but they use their skills of seduction as much, if not more so, than their apititude with any firearm. They assert power over men using not only their own finesse but their situation as attractive women and their ability to command the desires of men.
Though Riza is undoubtedly a comely woman she never asserts her sexuality to overcome strife. Despite her role as bodyguard and love interest to an attractive male character she is always serious and dutiful, never attempting to gain favour by seducing him, nor any of her superiors or enemies. Her position in life and apititude in battle have been solely gained by her merit as a person rather than as a woman.
This is not to say that Riza is not feminine in her own right, her strength and military expertise do not allow her to be defined as a masculine character. The most obvious example of this would be her one indulgence of long hair. Although strictly tied back for work, we see that on her days off she is inclined to wear it down along with a modest skirt. For someone so practical short hair would be far more suitable, and in the past and throughout the Ishbal War that was how she wore it. It was not until her first meeting with Winry that Riza notices how lovely long hair is. Although perhaps not overtly 'girly' this shows that Riza has some self awareness in regards to her appearance and the fact she is indeed a 'woman' as well as a 'soldier'.
The major difference between Riza and those classified within the Femme Fatale category is that she never uses her natural charms as a weapon. Femme Fatale is a title thats definition is vaguely negative, given to women whose superiority over men come from their wiles rather than their talents. Almost to say that woman's greatest weapon is actually due to a defect in the opposite sex. Riza breaks down this conviction, showing that attraction need not ever come into the equation. Her relationship with the male cast, even towards the one whom she is romantically linked with, are never overtly sexual. In return everyone appreciates Riza the person.
Conclusively, Riza does not fall into the stereotype known as the Femme Fatale. She does show us, however, that one can become a Femme Fatale without the need to parade ourselves as sexual beings. She does all this while also retaining her inate femininity, her compassion and her kindness, whilst making her way through war and strife.