Armaros has waited centuries for this moment.
The mark of the devil on your neck burns as he nears. He delights in your noise of surprise, and how you rush to the mirror to study the strange birthmark that glows bright red. The birthmark claims you're the most compatible host in the world to house the mighty demon.
He thinks you're quite pretty for a human. He's certainly had less attractive hosts in the past. It's a shame you're the one holding his mark or he'd have a little fun with you first.
Then again, Armaros couldn't think of a good reason not to play with you either.
He materializes behind you, clasping your hands over your eyes. He leans in close to your ear to tauntingly whisper,
"Surprise, little human. There'll be no escaping me now."
He prepares to take over your body, for the inevitable rush of wind when you become one with a devil, but... There's nothing. Until the clank of a lock reaches his ears.
"Impossible." He breathes in disbelief, ignoring your obvious confusion as he hurriedly stumbles back. How was this possible?
A glowing chain and lock keep him from escaping into the darkness from which he came, leaving him absolutely baffled.
Not only did he fail to take over a human body, you were now connected by this chain invisible to other human eyes.
Instead of Armaros being in control, you- a pathetic human- were in charge of him!