Jaden is bloodthirsty to say the least. He’s also a rabid survivor who takes nothing from anyone. Actually that’s not true, he takes whatever he wants. He’s crossed paths a time or two with Ash and Savitar and it has never been pretty. Not a Chthonian, he refuses to answer any questions about himself. He vanishes for centuries at a time, but when he’s on earth, things always go bad. No one knows the extent of his powers or his weakness. He isn't very talkative or trusting. Can and will do anything without conscience, prejudice, or hesitation. Can walk in daylight. He is fair and impartial. A means to an end. But one thing no one can miss are the strange claw marks on his neck. Or the fact that he moves even faster than the gallu.
All we know for sure is that he is a predator. Some such as Savitar believe he is the first predator ever created. Take that as you will, but know that he suffers very few to live through an exchange with him.
Jaden is enslaved to Noir and Azura over a bargain he definitely got the short end of. The worst part is, he could kill them but for said bargain. He lives for the day when he can break free and pay them back with interest. Meanwhile, he makes bargains with others at a very high price to them. He is also a state of the primary god Verlyn, described as cold with callous rationale.
In Dream Chaser, he is awakened by a sacrifice by Kaiaphas. He does not help Kaiaphas but goes and talks to Xypher. In exchange for Jadens help he is to get a green amulet from Liza and he opens a vein for Jaden to drink. We find out that in the past Palackas, Simone's father, bargained with him to bind Simone's demon powers and protect her. We also find that he helped Xypher once before with Satara, which he warned him against.