Kamui is the main character of the show, and is portrayed differently, depending on weather you've seen the manga, english dubbed movie, or the subbed tv series. I've seen both the dubbed movie and the subbed tv series. In the dubbed movie, he acts with a small attitude, and cares only for his friends, particularly Kotori, even though he does complain and whine a lot in the english version. In the subbed tv series, Kamui is cold, uncarring about everyone (at least within the episodes i've seen), and is ruthless in killing his enemies. He sticks tightly to his beliefs and is not persuaded easily. Kamui is the one who determines the path the future will take; destruction of the human race, or a normal future.
Kotori
Kotori is Fuuma's sister, and a potential yumeni, or dreamseer. In the manga, she's got a very friendly relationship with Kakyou, who saves her when she begins to 'die' in her own dreams, but in the anime and movie, she's a very happy and perky girl. The meaning of her name is "little bird," and it helps to portray the innocence she represents.
Fuuma
Fuma is Kotori's brother, and a childhood friend of Kamui. He and Kamui look very similar, a point that comes into deep play later in the series, and he starts out as a kind and loving character, who keeps an all-around big brother personality. Later, however, certian events cause him to loose his personality.. and his mind. TT;
Sorata
Sorata is the jokester/prankster of the group. He's quick to play, and likes to hit on Arashi a lot, but he has his serious moments in which show you that there's a lot more to him than what meets the eye.
Arashi
Arashi is a high-priestess, of whom works for Hinoto, and is also with the dragons of heaven, like Sorata. She's got a strong-will and a cold demeanor, but it all fades away when someone gets hurt, or when Sorata addresses her in the right way. She has the cool ability to pull a sword out of her hand without killing herself, and she dosen't seem to care for Sorata very much at first, though he seems to slowly be getting through to her.
Yuzuri
Yuzuri is probably the youngest member of the dragons of heaven, and is always accompanied by her spirit dog, Inuki. Ever since a child, she's felt bad because people can't see Inuki, but upon finding the dragons of heaven, she realized that they, and the dragons of Earth, could see her Inuki. Estatic that those few in the dragons of heaven don't think she's insane because they can see Inuki (normal people can't), she happily fights by their side.
Seiichiro
I haven't gotten to him in the anime yet, but from what I understand, he's a happy father of some beautiful children, and his wife is still alive. I *think* he's the 2nd oldest dragon of heaven, beaten by Karen, and he seems to be very close to Karen at times.
Karen
The oldest of the dragons of heaven (or so I believe), she feels the others, besides Seiichiro, are all too young to be involved in such battles that take place for the dragons of heaven, but dosen't like the idea of Seiichiro fighting because of his wife and kids. She has a 'noone will cry if I die' type of outlook on life, and fights as if she has nothing to loose (so i've seen from the little bit i've taken in.). She seems very wise for her age, even though her choice in dress isn't always that...appropriate. At least it isn't as bad as Kanoes.
Subaru
Houkto's brother. If i'm not mistaken, it is he and Seishiro that start the battles between the dragons of heaven and Earth, but that's only a summary i've come up with by watching the English version of the movie. He's a dragon of heaven, who really hates Seishiro for killing his sister. (TT I think Kakyou must hate him more.. After all, Kakyou *DID* love Hoktou..)
Satsuki
An odd but cold woman from the dragons of earth who loves only the machine in which she spends most of her time; Beast. She states that the machine loves her back, but such a thing seems weird. Beast is hooked up to every wire in Tokyo, and can use underground wires to launch surprise attacks.
Yuuto
A kwaii guy who reminds me of Rufus from FF7 (apperance-wise), he's a dragon of earth and the first person who brings up a fight with Sorata. He talks to Satsuki a lot, and has a kwaii attitude.
Nataku
Nataku is an android. Plain and simple. It seems to think Fuuma is it's father, for reasons even *I* don't understand. Nataku reminds me of Yue when he's in battle dress, and he uses the long piece of fabric that floats around him as a weapon. How Spiffy.
Seishiro
I don't know much about this guy, but I don't like him, because he made Kakyou's life a living bad-after-address. His eye is creepy, and he's a dragon of earth, which is enough to make him a badguy. He kills doves and fights with Subaru, not to mention he smokes, so you can see why I hate him.
Kakyou
The host of episode 0, or the OVA rather, Kakyou is the yumeni (dreamseer) that hates his life with a passion. He's stuck in a coma due to an attempted suicide, at least until the day Kamui desides the fate of the world, and he had met Hokuto in their dreams, falling in love with her. He was very upset when he saw Hokuto's death and could do nothing, so one can understand why he's so apt to stay in Kotori's dreams to protect her.
Hinoto
Hinoto is the main yumeni of the series (poor Kakyou..), and sees dreams of the future. She seems to be a bit naieve, only seeing what she wants to, even though her sister will say that she's right to see both good and bad. Hinoto's cool, but what happens to her at the end of the movie absolutely SUCKS, but I won't ruin it. She cannot speak or see, if I remember right, and only looks like she can, due to magic. She speaks through the minds of others, and tries to get Kamui to join the dragons of heaven.
Kanoe
Kanoe is Hinoto's sister, and she dresses rather bad, espcially in the movie. She's the head of the dragons of earth, as Hinoto is the head of the dragons of heaven, and she leeches off Hinoto's dreams. She can see Hinoto's dreams, but does not have the power to see her own, not being a full-fledged yumeni herself.
Hokuto
Subaru's sister and Kakyou's would-be love. She's also a priestess, and met Kakyou via their dreams. Oh what irony that when he sees his meeting her, he also sees her die. Poor Hokuto and Kakyou.