I'd say the Drake would enter the roleplay by making his presence known.
He had always been in the shadows, watching the adventures unfold, and never lifting a finger which could alter the natural course of events. The most of his presence you might be able to catch would be a fleeting shadow here, a stealthy footstep there, perhaps an ominous chuckle at times, but that would be it.
However, if you heard someone softly humming in the woods, you would have definitely been listening to Drake Lamenter.
If one of you could merely continue along until a point where everybody is alone, and someone hears mysterious humming during the full moon, goes out to find the humming, and sees Drake sitting in a small clearing whittling a small wooden figure.
It's clear that he doesn't have wings, or so the person will think, until by a trick of the moonlight, they see the faint outline of nearly invisibly folded wings made of shadow protruding from his back.
The person decides not to engage for now, but instead, looks for signs of the man who appears to have been watching them for some time now, and at night, follows the man on his small escapades, until eventually (this is where my first post will come in), he catches you watching him, but to no ill effect.