Old One is the Werejaguar incarnation of Midnight, the large black cat that appears on Evan’s bedroom wall mural of the Forest. Old One is as one might expect a tall muscular werewolf-like jaguar beast that acts as an altruistic-heroic interventionist in the story toward the end. Everyone loves when a stranger comes to the aid of an innocent victim, yet neither Seven nor Eva understand how Old One is in fact Midnight, nor to that end who even Midnight is, and to them it is just a miracle that this intimidating monster has come to their aid, specifically in his duel with Faye’s Draca in the River Payne. No human form of Midnight / Old One ever appears in the book, however, this cannot be ruled out by the author in future revisions.
Old One first animates for young Evan long ago, in the werecat’s pure panther form, on Evan’s bedroom wall mural (which Evan painted himself, unwittingly bestowing a power portal upon the picture), soon leading Evan into the dimension of French’s Forest, then later leading a future occupant of that same bedroom, Eva, sleeping beside that same mural, along that same Ruddy Stroll into her heart’s forest of dreams. ‘Midnight’ as Old One is known to them, acts as a reluctant guide to both of them, to those haunted, dream-time woods. He wishes them no harm, yet they plead and long to explore those dangerous woods. Midnight eventually feels he fails Evan, losing him forever to the Forest, thus, the were-jaguar then finally goes the extra distance to protect dear Eva, ultimately dueling with Draca to the bloodthirsty end in the River Payne.