Shadow Dragon by Lauren Esker

Sometimes you have to go through the darkness to find the light.

Azarias Caine is the Shadow Dragon, utilizing his shadow-shifting power to travel instantly between patches of darkness. Secretive by necessity, he works alone, always has, and his personal life is a mess. Until a last-minute escape sends him somewhere truly unexpected: into a lonely shut-in’s bedroom closet.
Gilly hasn’t left her house in years after a devastating accident left her with a paralyzing fear of the world outside … until a mysterious man stumbles out of nowhere and collapses on her floor.
There’s danger right behind him, but he makes Gilly feel more alive than she has in years. And she can sense him coming alive, too, the ice-cold loner thawing just for her.
A man who can go anywhere and a woman who can go nowhere just might be made for each other, if his past and hers don’t catch up to them first …