the characters in this manga all are multi-dimensional, and their expression of personalities lend a dramatic atmosphere to the story. the male mc is the usual good looking bad boy, and the female mc is the usual naive innocent cutie, however their characters are explored and magnified making us root for their happiness. the side characters did a great job in supporting the mc in making their love bloom. some characters seems big, however lost significance in just a short while, so it might throw you off.
the mentally unstable aspect of the characters are also a huge draw of this manga. every one of them have at least a little bit that's broken, and both of the mc is too broken that they can only fix each other. i really love that rei never change his psychopathic tendency, he is only moderated by kira's presence.
even though i love the development of the story, it is a little bit stretched. sometimes i feel a whole volume gone by without anything of significance happen. this is because of the style of art, where sometimes there is only one or two panels in a page and a lot of extreme closeup. this do make a more dramatic feeling, however progress is much slower. also one can get bored as they endlessly profess their love to each other, sometimes their touching and kissing are too much as nothing else is going on.
still, though their drama is a bit too dramatic, it is quite entertaining. the art is also very beautiful and light and pleasing to the eye. one can get lost in admiring them.