First of all, this manga is still being published, so my review can only touch on the chapters I've read this far, being those of the first two volumes as translated by Illuminati-Manga and Izumo no Ryuu.
Welcome to France, anno 1429, in the later part of the Hundred Years' War, where we meet the leader of a band of mercenaries, aptly named, as per the title, Pierre, who, when not on the field of battle, spends his time marauding and plundering. So doing, he tries to rob three men of all their goods, including their clothing, to find out one of them is actually a girl. Wanting to do the dirty, he is stopped when the girl begs him to leave her unravished, so she can travel to Orléans and fulfill her tasks there, to which she has been appointed by God Himself, after which she will submit willingly. For some reason he cannot really fathom, Pierre indeed does leave her be, thus allowing her to in fact become the Maid of Orléans, and from then on he will fight at her side.
Mercenary Pierre is yet another rendering of the story of Jeanne d'Arc, this time focusing solely on her campaigning years, as seen through the eyes of a man who starts out as a gruff and worldly dog of war, and who slowly is being redeemed by the grace of La Pucelle. As the first two volumes don't range beyond the victorious first campaign towards Reims, as of yet little more can be said about the greater story.
The art is great, reminding one perhaps mostly of the past arcs of Berserk. There is a lot of attention to detail, visible in the arms and armour, but also in the buildings, trappings, and backgrounds, making it in this aspect a lot akin to other historical series as Historie and Vinland Saga, but being more gritty and detailed in depicting the faces, and being without the annoying empty spaces especially Historie shows far too often: every panel in Mercenary Pierre is fully put to use.
It is obvious the illustrators know what they are drawing. Not only is there much attention to detail per se, but it is also quite correct, and it is clear that the creators of the manga have to some extent studied available work on the War and d'Arc's campaigns: not only are arms and utensils quite correct, for instance, but so also is the lay-out of the fortresses and cities mentioned. The attention to detail can also be found in little touches such as the (correct) map of the strategical situation around Orléans at the end of volume 1.
Quite a few pages show art with sexual content, and though these drawings are not fanservice per se, as they do tie in to the story, one may question the real use the profundity of sexual scenes has with regard to the quality of the story.
The attention to detail mentioned above is also visible in the story. Though the language used is at some points somewhat unwieldy (though this might be result of difficulty of translation), it is clear that attention is paid to making the characters think to some fashion as people of the place and age would think, and act as they should act. The issue of plunder by bands of mercenaries, including the enslavement of persons, especially women, is used often in this fashion, and though the phrasings used would make the reader think that we're dealing with stereotypical images of rape and destroy, the manga shows how such tours of marauding had an impact on logistics and the local economy, even showing the soldiers' camp as a movable economic unit in and of itself.
Issues of sexual morals and gender are raised somewhat overly often, and it is here that all too often modern-day morality seems to raise its head, though the manga tries to portray the facts of mercenary life and how it conflicts with Christian morality.
With regard to the characters, as always happens when she appears in whatever story, Jeanne steals the show. Portrayals of the Maid of Orléans are almost as varied as those of Jesus, ranging from a madwoman to one truly divinely inspired, from a naive pawn to a master tactician and demagogue. Recent approaches tend to emphasize Jeanne's human side, her doubts about her mission, and her intelligence, or common sense, when dealing with the more learned and more worldly.
Mercenary Pierre plays it somewhat more simple, displaying Jeanne as a young girl, overly naive, believing in her mission, and focusing heavily on Christian morality and propriety. Much is made, too, of her charisma, which is strong enough to make her appear larger than life and encourage men on the battlefield with her presence alone.
Her charisma and conviction seem to strongly influence the men and women she interacts with, most notably Pierre and his band, and their manners change visibly. Quite touching is how her sense of mercy and equality of all life is portrayed and shown to rub off on the gruff mercenaries.
Of course, there are downsides. Focusing so heavily on Pierre and Jeanne, much of the greater story is left somewhat vague. Jeanne seems overly naive, irritatingly so at times, while Pierre and his band seem to be redeemed somewhat too quickly. More annoying is that much use is made of the old "good simple soldier, bad conniving noble" cliché, though the fact that Jeanne was actively opposed by many nobles takes some of the steam out of the annoyance. Somewhat irritating, too, is the heavy emphasis placed on issues of sexual practice and morality.
As for the translation, in general it is of a good quality. The story is clear, and many names and terms are consistently used. A nice touch, too, is how the actively mentioned use of a northern vernacular by the mercenaries vis-a-vis the official French is shown through use of some dialect in English, though I wouldn't know whether such use is made of dialect in the Japanese original. Sometimes the translation is somewhat unwieldy, especially when it seems that a technical term is used with which the translator is unacquainted. More grating is that many proper names are incorrect (such as the consistent use of 'Tourel' for the fortress of 'Les Tourelles', and, more seriously, 'Lens' for 'Reims'), though, again, this might be an issue in the original Japanese version.
All in all, I'm pretty impressed by the manga, and am actively awaiting more translated chapters and am hoping for an official release.