Wings of Fire: Bound

When Swordtail found out Luna was dead, he was broken. His funny, determined, Luna was dead. The breath of evil was defeated, but the world still felt like it needed saving, because all his friends were acting different. But Luna starts talking to him in his head, at first he thinks he's imagining her, but soon realizes she's alive, sort of. Then, he finds himself on an adventure! But he hast to keep that Luna's alive a secret, for she warns him that if he tells anyone, she'll be in great danger.