Now, who is Riza Hawkeye?
This section contains heavy spoilers for both the manga and anime, so please read at your own risk.
To put it simply, Riza Hawkeye is a First Lieutenant in Amestris' army serving her commanding officer, Colonel (and State Alchemist) Roy Mustang. She is younger than the 29 year old Colonel, but tends to act twice his age. Not much is known about her past before joining the military, but it is known that she served as a sharpshooter during the Ishbar/Ishvar/Ishval War prior to the series taking place. It is there that she most likely became aquainted with Roy, marking the beginning of a long relationship filled with loyalty, compassion, and dedication. Although she does not appear in the manga or anime as frequently as the Elric brothers (after all, it is Fullmetal Alchemist) or even Roy, she plays an important role in all aspects of the story.
Hawkeye gives off the impression that she is extremely calm and aloof--you can actually see this in her appearance, too. Even though she's grown her hair out, she always keeps it pinned back and her uniform immaculate. She takes everything very, very seriously and secretly scares all of her comrades with this intensity. However, as Roy notes, she actually is very kind. She takes in Black Hayate（即小黑，那个小狗） when Fuery cannot find the dog an owner, and basically takes him everywhere she feels he wouldn't impose. Even little scenes like her telling Winry that she has grown up to be "very pretty" with a smile on her face add to this element of her character. Also, there are scenes scattered throughout the manga and anime that show her interactions with the Elric brothers being filled with compassion and patience. If anything, she is very protective of them (especially Alphonse), but that could probably be said about everyone she cares for.
Hawkeye is "normal" like Hughes in the sense that she cannot use alchemy. Instead, she relies on pistols and rifles to keep things in order--even Roy when he's slacking on paper work, or to potty train Black Hayate. She has an amazing shot, but even that phrase probably doesn't do her justice. When Roy is unable to use his Flame Alchemy, we see Hawkeye literally kicking him down protect him from his own forgetfulness/recklessness. Unlike Hughes, however, she isn't afraid to get too deep into a situation at Roy's request.
Maybe the biggest aspect of Riza Hawkeye's character is her relationship with Roy Mustang. Even if you were to not count them as being a possible "romantic" couple, Roy and Hawkeye have a very deep and personal understanding of each other. While all of his subordinates are loyal to him and his cause despite the fact that Roy somehow manages to piss off someone every once in a while, Hawkeye is the one that he confides in the most; especially after Hughes' tragic (and slightly traumatizing) death. When Hughes dies, Hawkeye seems to become his main support system, the one he tells to get information "quickly" and "secretly," the one he confesses any weakness to. Hawkeye tells Winry in chapter 25 of the manga that she chooses to stay with him and protect him, which says a lot about her character considering how far up the ranks she might have been able to go without him "tying" her down. There is something about Roy that she responds to, whether it be his vision for a better future, or his nobility, or just the fact that she really does love him. The only time she really loses control of her composure is when Lust begins taunting her about Roy's (supposed) death--Hawkeye literally breaks down and begins screaming, crying, pumping bullets into Lust. When she finally runs out of ammo and Lust is still alive and mocking her (despite the fact that Hawkeye nails her in the head and chest perfectly), Hawkeye sinks to the floor having, as Lust explains, "lost the will to live."
At one point in the anime, the storyline takes a huge divergence from what happens in the manga. This basically has to do with Hawkeye helping Roy bring down King Bradley, and then cutting apples for him after he loses his left eye in the process. Jamie and Lexa（这个网站的两个站长，猜想应该就是这篇文的作者） sort of get annoyed with the anime, but thought it was worth mentioning at least for the cute apple scene.
Hawkeye is a very deep character, but people will often disregard the fact that she is her own, independent person and not just Roy's little pet (probably because of the aforementioned scene). While her past is still being uncovered slowly in the manga there's always more and more going on with her as the story progresses. Will she help Roy achieve his goal of leading Amestris? Will she die trying? The future is still untold.
并不是想贴一段费解的英文在blog上，只不过怕翻译过来很多意思便不能体会。这段文字来自一个叫做A Day Without Rain网站，它对自己的定义是这样的：This is the official fanlisting for the character Riza Hawkeye of the anime and manga Full Metal Alchemist. 很诧异原来有这样一个网站，聚集了来自世界各地对Riza这个小配角的爱，单单对Riza完全独立的爱，而并非依附在别的角色之上。Hawkeye is a very deep character, but people will often disregard the fact that she is her own, independent person and not just Roy's little pet.（Hawkeye是一个极赋深度的角色，但人们常常会忽略了一个事实：她就是一个她独立的自己，而并非只是Roy的小宠物)。 对于这句话很有感触，当几乎所有的百度结果，所有的论坛被诸如“R*R“，”RR王道“等字眼霸占的时候，很让人怀疑甚至是遗憾Riza是否是以本身被赋予的性格而被大家提及的。我并不是RR的反对者，但我是更倾向于Riza的，仅出于对这个形象的赞赏。正如站长Lexa说的，Hawkeye just kicks so much butt--who knew how handy a semi-automatic weapon could be?!No, but seriously... she has such extreme dedication to her cause and knows exactly where she wants to go and who she wants to go with. 当然，Riza并不是一个真实的人物，作为漫画的一部分，她的性格她的处事完全是作者虚拟的。我，或者说Lexa，Jamie和更多A Day Without Rain的members对于Riza的喜爱，归根到底都是对内心所认同并期望的另一个自我的喜爱吧。