I like this manga a lot.
Aria, the main girl, is strong-willed, fast-paced, ambitious, and sort of rash. She's a good fighter. She kicks ass--as the other comment says.
When she met Sakura (the main guy), the world of reality that she lives in crumbled. She learned of the curse that is passed down in her family. The demon is out to kill all of her relatives--all 4000 of them--because of a grudge (of sort) that he held 400 years ago with the ancestor of the family.
Present day, the demon had possessed the body of Sakura. The demon is threatened to take over Sakura's body and go on a murder rampage. The one with the power to stop the demon's conscious to take over Sakura's body is--you guess it--Aria.
The manga, though, pretty complex--still left some loose ends, questions that aren't answered. (it's completely scanlated). But nothing serious. If you don't think too hard about the plot, you wouldn't notice it, haha, and you shouldn't since it's meant for entertainment after all... I wish the story was longer (it's 26 chapters)... Some of the characters are not well developed at all--Come to think of it, I don't even think the main characters are well developed. The whole manga focuses a lot on the background story, which thankfully is quite interesting--and sort of ignored the characterization a bit here and there. A bit disappointed about that since I do like Aria and Sakura. Would loved to see their characters a bit more outside the fights and the worry and the crying...
The romance is good. We knew they had something for each other from the very beginning, but it's not expressed mutually until around the middle (?) of the manga. Not a handi or anything; I think it's a nice change of pace.
Aria didn't realize she's in love with Sakura until towards the end...haha
The drawing: reminds me a bit of CLAMP's and Nakamura Yoshiki (of Tokyo Crazy Paradise)'s art work. ... on a second thought, that might not be the best comparison, but right now those are the two names that popped into my head. That is to say; the art is very nice. The proportion of the body is superb. The face is weird sometimes, but not something to be alarmed about--still quite well drawn. The clothes --of thank god for this--is on the good side! (I just got off reading Tokyo Crazy Paradise again and couldn't keep the thought of how bad the fashion was to myself..sorry). If you are looking for a good fight-related manga...Obviously there are some supernatural elements thrown in, which in my opinion makes the fights some what harder to follow. Is it a good fight-related manga? I'd say average since the fights didn't get my blood pumping.
Despite all the complaints I had about this manga (mainly just the length of the manga), I really did enjoyed it, and because of that I rated a 9.