There is a bit more background to this character, as I see you've noticed quite quickly. The info about the Kyton Demon in general can be found in D&D 3rd edition Creatures Handbook (or whatever it's called). The Kyton Demon is my favorite "monster" of them all.
And as a little idea here comes what I've used him for in my campaign:
Raign is a character I've "condemned" to follow (maybe just for a short while) with a group of Pelionic Monks and Paladins (Pelion is the "Look-at-me-I'm-so-rightous" kinda deity in my campaign.) Only one of the monks (a PC) do not know that he is a demon, but he quickly finds that something is amiss (a lot of fun when the PC player is very edgy about these things). As soon as the PC finds out he is a Kyton Demon, a servant of evil, he quickly condemn the beast. The only thing is that the PC is actually a half-orc raised among the Monks in the monestary... You can maybe imagine the point I wish to show the PC. If not: DO NOT JUDGE BEFORE YOU KNOW THE TALE!
I used this in the first "Intro" campaign session which I ran alone with this PC. I had sensed that the PC player had a bit "odd" views on how he would play his PC. So just to give him a little hint of what the consequences of his actions would be, I made this little intro story just for his character. Go to Comment
The chains grow out from different places on is body and is wrapped around him, functioning as armor and can be used as assualt weapons. If you want to know about the Kyton Demon look it up in D&D Monsters Guide for 3rd ed. Go to Comment