I found some really good spoilers for any one who would like spoilers for this series! Some of these spoilers will not be revealed in the anime. Here they are. If you have some spoilers too, please share.
Taito Kurogane
Taito has a split personality called "Dark Rabbit". (Taito's beserk mode) The Dark Rabbit's curse is the power to Reject. ( The power to reject the existance of anything) In Dark Rabbit mode, he can see the contructs of everything which are made up of words that speak of the past and future of the object. Every object and things is covered in those words. This is the Prophecy. The prophecy affects all things. To a limited degree, he can earse the words, thereby turning an object into nothingness. His body contains the power of Ramiel and Lilith. The one he truely loved was Haruka.
Haruka Shigure
She's a being created to observe Taito but fell in love with him in the process. She's the God(s) on the other side of the moon itself
Izumi Aomi
was appointed the secretary of the student council, on the condition that she stops smoking. Thereafter she was always seen with a lollipop in her mouth. She is dying from a brain tumor. She won't live past the age of 18.
To learn more about the rest of the characters: type itsukatenmanokurousagi.wikia.com in the URL. Go over the character tab and click either male or female. You can click on "list of characters". But it won't give you much info. Whereas if you click either male or female, it will give you a lot of info.
Taito was supposed to have his own training separated from others. But he was kind of duped in the end. Kurosu and his Military subjected him to a series of experiments that turned him into Dark Rabbit. The experiments had failed previously as the subjects had all died. But because of Taito's conditional immortality, they wanted to use him. During the experiments, he kept dying and coming back to life again and again. So in the end, the experiment was a 'success' but the Dark Rabbit went berserk, broke out of the Military and went to Makuae (home of the demons and where Mirai's mother was).Taken from Mangafox
Yūichi Philier Cross
There are still a lot of mysteries with regards to Kurosu. Everyone who fought him including Hinata and Himea thinks that he's not human. But he claims to be a human. Himea used a detection magic on him and it turns out that he is human. Though he created the Military 350 years ago, with the purpose of overturning the prophecy. He also seems to be in some sort of 'love' with Liir, the Holy Ground at Miyasaka High. The strange thing was that he also was the 7th Student Council president. Taken from Mangafox