A slice of pretty of just the right kind. This manga has all the characteristic features of Aki’s works, but this is my personal favorite. If you’re not familiar with her style, I’ll explain the best I can. But to sum it up for the brevity: on the span of the first 4 volumes this manga is well worth your time, unless you have a particularly strong aversion to female-oriented works, and it doesn’t contain shounen-ai, despite what you could think from the description. The only thing that worries me is that it does become lazier as the volumes go.

So, Aki is one of the high-level authors of female-oriented manga with her own dedicated cult following. Which basically means (all of this is relevant to Aruosumente):

“High level”: Many of her works can be recommended even to people outside of the demographic. It’s unclear if everyone can like them, but they certainly surpass the limitations set on the more typical shoujo or josei. And if you are a part of the demographic, it’s only logical to pay attention to something so good.

“Female oriented” is reflected in style and some aspects of writing. The art is light-shaded, frilly and with the aim to be traditionally beautiful. The writing is focused on characters, with the casts being mostly male and relatively small-scale.

And Aki herself has two huge strengths as a mangaka. She can draw well and she can write well. Nah, it’s not that self-explanatory, I haven’t covered the subjects, did I?
She is famous for her extremely beautiful and detailed art, and it’s truly a treat, her colored pages beg for immediate framing. She formulates characters' lines well. She also is obviously an intelligent and well-read person. Most of her works have a philosophical subtext or are outright concerned with a philosophical question. She likes non-linear narratives, eschews exposition and freely leaves some steps in the story for readers to reconstruct themselves.
On the other hand, I can’t say that she is a brilliant storyteller plot-wise – her concepts are usually good, but the development may be less than you expect initially, and the stories are small in scope, even though sometimes you earnestly expect and want at least a tiny bit more of epicness. My personal pert peeve is that she sort of discriminates – the characters besides the main cast, who she is interested in, are drawn schematically, and servants often do comedic relief, which is classist (I try to ignore it, but it gets a bit annoying after a time). The backgrounds may also be generic sometimes, with main attention on people, symbolic elements and décor.
Setting-wise she seems to have the same symbols in many of her works. She likes angels (and can interpret them in interesting ways), highest-class beauties (beauty is approached not only graphically, but thematically too), high society and magical stones.
All in all she is a mangaka worth knowing and keeping an eye on.

Oh, and also duty calls me to note that Aki’s works are relatively shipping-free. There’re situations that can be seen as shipping bait, even in Aruosumente, but this also can be safely and easily ignored, since there is no annoying undercover tension so characteristic of many female-oriented manga, especially josei. Characters don’t blush without reason or look at each other longingly out of context, etc.

And Aruosumente also has a story I’d go read, if it was a novel. What seals the deal for me is the main character. Legna the oracle is one of the rare protagonists in manga – he is a person without imagination, stubborn, closed off, yet very dutiful and loyal. He is this amazing type of character who is not self-insert or reactive, but instead acts based on his own set of ideas and ideals and within his limitations. Despite his personality and position, he must go out and far from his comfort zone, which leads to plenty of development for his character and for plenty of comedic situations. The character-driven comedy here is superb.
Legna’s venture in the world of politics yields unexpected results, makes him meet new people and learn new things about himself, as well as puts him in danger. It also starts to unfold another, now much more personal mystery in his life. There're several other major characters with their own complex stories and view-points, connected in various ways to the events Legna tries to unfold.

Now, a long time from last chapter I am not mesmerized enough to say that the story does have problems. It lacks in scope for my taste (I’d prefer to see it go further into their world, and the castle life to be slightly less family-like), it also has feels fanservice, but the secret behind the events holds my interest, and, damn, personally I reread it from time to time, simply because the writing and art are so tasty. I must say that the historical fantasy (it’s set in something vaguely European in style), the main character being a religious figure and the investigation being the main story point remind me a lot of The Name of the Rose by Umberto Eco, and this comparison doesn’t seem to me to be in bad taste.

Aruosumente is fun, intelligent, beautiful and addictive (now, if only it was released faster), I can’t recommend it enough, though it is ongoing so I can’t vouch it will end satisfactory. The only warning I can give is that it may not suit all of the readers who prefer the style of male-oriented manga and that the storytelling seems to be aimed at people with reading experience, who are accustomed to quickly piecing the things together. But even if you doubt – check it out, it can become either a cherry on top of you list of shoujo and josei or an unexpected good surprise and distraction from the usual routine of shounen and seinen.