first of all, this is one of those manga which grow, getting better as the story evolves. it starts off light-hearted and somewhat silly, but as the story comes along, more serious topics are woven in,(e.g. discrimination, selfsacrificing, keeping up appearances) important characters are added and it gets more complex. though it does have a few flaws, overall enjoyment was good, i found myself laughing quite a few times even while rereading. now in more detail: it's light shounen ai, (they kiss and express their love for each other, nothing more), but a tiny bit more obvious than silver diamond, the authors other major work. the comedy isof mostly of the slapstick kind and relies on silly answers as well as the main characters being (incredibly) slow on the uptake or acting contrary to what's expected of them considering their position.
it didn't really bother me, but it's worth criticizing that sometimes commonplaces/ stereotypes which didn't fit into the medieval world as the setting were used for jokes (such as reference to an all girls high)

Story:
in the beginning i had the impression the artist wasn't really sure where he wanted the story to go, resulting in some slight inconsistencies before it does kick off (like characters knowing about things without an explanation why they would or demons (/blood) not knowing about some things it'd be more sensible if he did)
it consists of one main story line and a couple short stories, mainly backflashes on some of the characters pasts, more or less integrated into the main story (about rapunzel and wild, blood, ishuca, ishucas grandmother and the demon kaiser)
the storyline seems rather simple at first, a classical adventure plot: boy meets demon, they go on a journey, meet all kind of people and get involved in their business, get caught up in stuff happening due to what took place in the past and as they try to deal with it, others they met start to get drawn into it all too - resulting in a more and more complex interaction, since even people of the same factions (temple vs. demons) have different motives and each work on their own goal.
in my opinion, this is what makes this overall a good, interesting manga and what kept me reading despite any other shortcomings!

i really like how it's not just good vs bad and you can't clearly tell for everyone from the beginning who is - or might be in the future - on whose side

Characters:
there are the main two pairs of demon x boy, (Blood and Ishuca, Rapunzel and Wild) both based on the concept 'cunning, adult' (demon) vs. 'cute, innocent, strongwilled' (boy) which at first seems flat and cliché, since it's commonly used in yaoi/shounen ai. though they do grow throughout their adventures, this basic concept is never abandoned, perhaps because it's needed for a lot of the comedy interjected every now and then
however, as the story progresses, other characters appear, with a more complex personality which develops as well (e.g. the monk Sellghi), thus adding to the story and making it far better than with just the main characters

Art:
the quality varies throughout the manga, most times it's welldrawn, occasionally the bodys feel a bit misproportioned (too large hand/ feet), so i rated it down to a six

as i said, overall i enjoyed it quite a bit and i'm still looking forward to every release - naturally i recommend reading if this review got you a bit interested and you like fantasy/ adventure stories and don't mind shounen ai