[ t o u m a ]
Touma Hashiba has lived with his father in a modern high-rise mansion (i.e. apartment) in Osaka since his parents divorced when he was twelve. His mother has the spare key to drop in whenever she wants. Touma's father's lab is in Kyoto. In sunrise's first draft, Touma's grandfather owned a Buddhism temple, and Shuu is a foreign student from China who stayed there (that is, Shuu and Touma grew up together) It was then changed to the current setting. However, doujinshi in Japan like the idea, and wrote a lot of story based on it.
Touma has an IQ of 250, which means during the TV series he had the intellectual capability of a 35 year old (His mom did say he acted like an old person) Because of his intellect, others would call him a Living Computer or genius.
Adults don't treat him like a kid, so Touma often acts like an adult (he's the youngest of the Troopers) He actually enjoys studying. He also likes reading detective stories.
Though he is usually a cool, self-possessed person, matching his computer-like intellect, his emotions can also make him as violent as a tornado. The Troopers are the first real friends he's ever had and he'll do anything to protect them.
Touma's blood is AB. By the little Japanese blood-personality chart, that means he has a very high pride, a tendency to insult, and often takes revenge.

[ s e i j i ]
Seiji Date was quite rebellious when he was younger. It wasn't that he didn't like kendo, he didn't like all the etiquette. To teach him restraint, his grandfather made him study bonsai and the bamboo flute in order to teach Seiji how to calm himself. For generations, the Date family has passed down the story of a yoroi, actually Kourin.
When Seiji was very young his health was very fragile. His family dressed him up as a girl (in the belief that girls are easier to raise than boys.) Seiji doesn't remember this.
In elementary school, Seiji's friends usually cried whenever they saw both of his eyes, saying it looked scary. Seiji's eyesight is very sharp and the paleness of his eyes makes them look hard. Yayoi suggested Seiji cover one of his eyes so his friends wouldn't be scared. Also during that time, Seiji's sister would use him as a toy for dress up. Yayoi has a picture of him with ribbons in his hair.
Seiji is very proper, and speaks a very formal of Japanese. He hates lies and evil. Though often in control and calm, Seiji can be driven into a nearly blind rage. He is identified as the pretty boy of the group.
It caused quite an uproar among Trooper fans when Seiji drove Nasti's jeep when he was only 14. The legal driving age in Japan is 18. He also won a race when he was sixteen.
Except for Seiji's grandfather, women are more powerful in his family.

All of the above info are taken straight from Nether Realm.

[ r e l a t i o n s h i p ]
The relationship between Touma and Seiji is only in my imagination, and those of you with the same thoughts are welcomed to join this fanlisting, whether it'd be just plain teasing shounen ai or hardcore yaoi lemon... ^_~