Mercury Raine: Twenty and One by Sarah M. Eden

Mercury Raine has spent his entire life surrounded by ghosts. Little about them can surprise him any longer. But when the Violet Giant, a ghost well over seven feet tall and built like a boulder, floats into his local pub, Mercury is as shocked as everyone else. And when the mysterious mountain of a specter knows Mercury at first glance, he is justifiably wary.

Mercury’s identity is a closely guarded secret. His past is a mystery even to himself. And, for the first time in his life, the fortifications around his heart have begun to crack. If he can make the Violet Giant one of his ghosts, the threat the phantom poses could be minimized. But few things, Mercury will soon discover, are at all what they seem, and what began as merely complicated may instead prove deeply dangerous.