Dreamers — Tami Veldura

The world is divided into two types of people: the dreamers who live vibrant lives and the warriors who defend them from nightmares.
Larz is a warrior, honed to be faster, stronger, and smarter than any evil. He has solved puzzles, answered riddles, and fought the life of his assigned dreamer without ever knowing more than their names.

But there are secrets hidden in dreams and one is in Rayan's mind, locked in a chest, and guarded by a dragon. Rayan locked it there himself. But now he wants it back.