You know who I've realized is one of the best examples of an anime strong female character? Esdeath!
Think about it:
1. Yes she's incredibly beautiful (with both men and women in the actual story wanting to tap that), but surprisingly she has next to no real fanservice. The anime adds a few fanservice scenes (her in a shower, her wearing just a shirt while trying to seduce Tatsumi, her trying to fluster him by wearing just a bra and pants when they're in that beach illusion), but even then none of them are thrown in just for fan service (as in, they actually have reasons for happening) and none of them go that far (unlike some other well-known anime/manga series...). She's never thrown into a scene just for fanservice, which is really a nice change from most anime series nowadays.
2. She's a goddamn BEAST in combat without being a Mary-Sue, since she worked her ass off to get to the top of the Empire and is near-invincible but in a way that properly sets her up as the final boss and not as a Villain Sue. She's also a tactical genius who nearly wins on multiple occasions through legitimate power and strategy without it being dumb Mary Sue luck. Also, the respect/fear given to her in-universe by allies and foes alike feels so genuine and not like anyone is Character-Shilling her.
3. She has a well-done backstory that does a solid job at explaining why she became a sociopath, and manages to show that she cannot be redeemed (no "Power of Friendship" for this girl) and is DEFINITELY a monster (such as letting her men pillage, ****, and slaughter their foes after every win) while also having redeeming qualities (She's an excellent boss, who gives her massive salary to her subordinates since she isn't interested in wealth, she is a big sister figure to Seryu who comforts her when she is upset about having to protect the scumbag Bolic [yes, even SERYU didn't want to save his worthless life but she was ordered to] and tells her to take a break and play soccer with some nearby kids, and comforts Seryu when Dr. Stylish [her father figure] dies. She also eats and talks alongside her soldiers during military campaigns, and encouraged Bols to take off his mask and not be afraid of his facial appearance in front of others. She also notably never forces herself on Tatsumi, even though you'd expect her to since it fits with her "Strong rule over the weak" policy and she lets her men do the same. Hell, she never does anything worse than 1 or 2 kisses on his lips without his permission, and even saves him when 2 women trying taking advantage of him in prison).
In short, Esdeath is one of anime's best examples of a well-made Strong Female Character. Well, asides from what she lets her soldiers do in the manga.
