The Captain is the last line of defense between you and the attacking horde, and he's a few meters away from you (about ten feet). His fighting guards are ahead of him, and currently holding off the main horde. Next to the Cpt there are the archers with magical bows and arrows, currently effectively holding back the horde.

The spirit in Keystone's head is like a second voice in his head, and is much less intrusive than any kind of spirit that actually hijacks a spot inside his head. It's just there, occupying some physical space inside of him(not noticeable). You can try talking to it, see how it responds.