Human Demons

As an example of the kind of thing I'm looking at:

Watching Pirates of the Carribean, it struck me that Commodore Norrington is much like a Demon for Elizabeth Swann. There is a definite, uncomfortable relationship. He has access to relatively vast abilities she generally does not(military command, control of a ship), and is generally well-disposed to her, but wants things she's not necessarily willing to give.

So when Elizabeth needs the help of the british fleet to save Will Turner, she has to negotiate with Norrington. In fact, the scene where she promises to marry him in order to get his help strikes me as a Binding scene. Certainly she seems to give up part of her Humanity(as Identity/Independence) when she makes that bargain.

Now, you could present Norrington in game terms as an Immanent Demon with a Need for something like Good Uppercrust Lifestyle(including lady wife) and a Desire for Law, or something of the sort. Elizabeth, as the only eligible lady, has some pull already, and may have Pacted a few times before, but this time the Pacting fails, because Norrington gets a lot of bonuses to resist saving the life of the rival for his lady's affections. So she chooses to Bind, straight up, because saving Will is that important. Norrington's bonuses vanish, because the form of Binding(betrothal) kicks Will's chances with Elizabeth straight out the window. Norrington agrees, story continues...

Problem is, even Immanent demons are kind of clumsy at being humans, mechanically, since Norrington's Cover would fatigue him, and he has no Humanity of his own. In the right kind of setting, with the proper definitions of Demon and Humanity, this isn't an issue, but...

Does anyone have any thoughts on how to get fully Human (mechanic-wise) NPCs interacting with PCs under the Demon rules? Where they fulfill a similar role to demons but without having a Power, would be my best terms, I guess. Like a setting rule that Humanity replaces Power in the contested rolls, and appropriate abilities do not fatigue? Are there significant balance issues I'm not seeing? I'd appreciate any thoughts on the matter.