Basic Summary of Role in Book 1: Partials:
Jayden is a soldier from the Defense Grid. He is first introduced as Madison Sato's (Kira's best friend and also adopted sister) brother - not adopted, but by blood - and also the only one, along with Madison, who is immune to RM. More is found about him during the first Salvage Run he does with Kira (that we know of). He is something of a natural leader, calling everybody by their last names (Kira - Walker, Marcus - Valencia). He does, in a way though, seem cold and unfeeling as his job and duty is more important than human lives. When Gianna and Mr. Andrews, the two civvies (slang for civilians) are imprisoned by a planned attack, and Mr. Andrews is stuck, he is willing to let him die to save the rest (some may call this good planning), while Kira doesn't give up until she realizes that he is dead. He is untrusting to big farms and Native Indians.
As said before, he is a bit cold and unfeeling. He is hella' sarcastic and extremely witty, wry, and dry (to an extent of being rude)
".. And thank you very much for the attitude. It's delightful to have you and your wit on this run."
- Jayden to Kira
".. And your mother's already in hell, so I'm sure you'll be seeing her soon."
- Jayden to Marcus
Though it is not clear, Jayden may feel something for Kira. Whether she returns the feelings or not is unclear as well, but it seems that she enjoys teasing, and sometimes even leading him on.
".. Marcus hopped down to the street. Both he and Jayden held up a hand to help Kira down. In a whim of mischief, she took both hands, and smiled inwardly, as they helped her down with sullen scowls."
Marcus: They exchange insults [ as shown in the Personality section, 2nd quote]
Gianna: They come to many disagreements, and argue about nearly everything