CTFC members can feast on this info:
Full Real Name: Ruo Chuin
Seishi Name: Tomo
First Appears: Episode 35 of the anime
Birthplace: He was an abandoned child, so that's not known
Age and Birthday: 21, October 13
Family: Abandoned him, but I suppose someone had to raise him...
Height: 184 cm --> 6'0"
Blood Type: AB
Seishi Ability: Illusion spells using a shin, a little teeny clam-like thingy
Hair Color: Dark grey, maybe silvery
Eye Color: Eh...yellow?

Appearance:

*shudders*

Personality:
I've already established that he's psycho and there's not much else I can add to that. He takes a perverse pleasure in torturing his enemies. Okay, wouldn't we all? But he actually has the means with which to mess people up in a big way. I'm not too fond of him, needless to say.

Usefulness:
Tomo is an exceptionally gifted magician...his illusions are so convincing that it can fool even other magicians into believing it's the real thing (like Chichiri). He can also save scenes in his shin so that he can take a look at them later (is that like how they save holograms in Star Trek? ^_^). What Tomo doesn't count on, however, is how damn devoted those Suzaku people are to each other (and some unexpected help they receive along the way)! If the illusions he has created fail for whatever rea son, they could be his downfall...

Thoughts:
Ehhh...I guess I kind of feel badly that Tomo has feelings for Nakago (and thus it can be argued that much, if not all, of what he does is for Nakago's sake), meanwhile Nakago hardly gives him the time of day. But that feeling should pass in no time :).