A big gray enigma, that's what Grayson Mora is.
Grayson, born in Sacramento (24.73), and his daughter Doe, age eight, encounter Lauren's group on the road north. Grayson is "a tall, thin, Black Latino, quiet, protective of his child, yet tentative, somehow" (23.102). That hesitation of his turns out to be because he has hyperempathy syndrome, too, just like Lauren and a few others. At first, he only sticks around with her group because his daughter, Doe, befriends Tori Solis (23.102).
Lauren's able to figure out that Grayson and Doe, like Emery and Tori, are sharers (people who have hyperempathy syndrome); that's because they all have an odd "tentativeness and touchiness—not wanting to be touched" (24.51). Lauren's encounter with other people who have hyperempathy syndrome plays out more in this book's sequel, Parable of the Talents. But it's safe to say that meeting other sharers is a startling experience for Lauren. She's not entirely sure what to make of it.
For his part, Grayson is startled to see Lauren hanging out with people who aren't sharers (24.92-95). And his hyperempathy doesn't seem to make him particularly compassionate—Lauren tests this out by purposefully stumbling to see if he comes to her aid, which he doesn't do (24.96-97). Oh, well. But yeah, maybe hyperempathy and compassion don't always go together. That seems part of the point of Grayson Mora being in this book, in fact: he contrasts with Lauren.
At the end of the novel, Grayson agrees to stay on Bankole's land (25.66), but he remains something of a mystery to everyone.