(Anton Yelchin as Seth)
Different from both his siblings, Seth doesn't remember much about his parents so the prejudice that they have to face because of their parents' actions didn't feel as personal. Seth doesn't care much about the past, he was all about the moment, the right now. He's a little bit reckless and has edges so sharp it draws blood everytime he bumps against someone.
He met his Bond-ghost Darling when he was six, bonded with her when he was eight much to the consternation of others. His was the youngest bond ever and people are waiting for it to fail, but even though the situation between Seth and Darling isn't quite ideal, it works.
When most ghosts look faded and grey the longer they exists in the world, when Seth meets Darling, she is vivid in color and she stays that way the few times they see each other which told Seth that Darling isn't dead but that she is unconscious somehow.
Darling keeps her real name and her situation close to her chest even from Seth and Seth doesn't really care as long as she does her job, at least, that's what he tells himself when Darling disappears once or twice to visit wherever her body is.
(Isabelle Fuhrman as Darling)
Unlike the relationship between the twins and their bond-ghosts, Seth and Darling's relationship is a lot less like friends and closer to business partners. But it is no lie that they are one of the best Reaper teams and that both understood the other really well despite that they don't share anything personal about each other.
What they have--their Bond--was personal enough for their tastes.
Darling is an odd one from the start, quiet, watchful and wary, she drifts in and out of the Matthews house. She is perhaps the ghost that makes the hardest effort to look alive from the vivid colors that emanates from her to her clothes that always changes day by day. And she grows with Seth back from when Seth was six, Darling also looked six and now that Seth is seventeen, Darling also looks seventeen.
She is secretive and has a wicked sense of humor which rarely shows. She loves a good brawl and knows how to fight in the dirtiest day possible. She takes her job seriously and watches over Seth when he sleeps like a hawk guarding over her territory.
Being a Bond-ghost she is given a choice once in a while to possess Seth for good behavior or for protection but Darling usually only uses his body to eat, to feel and taste food again.
Lately she's been more secretive than ever and it strains their partnership but neither of them knows how to fix it.
