Necronomicon- Protective Spells

Following me clumsily to the study, he asked for some whiskey to steady his nerves. I forbore to question him, but waited till he felt like beginning whatever he wanted to say. At length he ventured some information in a choking voice.
     “Asenath has gone, Dan. We had a long talk last night while the servants were out, and I made her promise to stop preying on me. Of course I had certain—certain occult defences I never told you about. She had to give in, but got frightfully angry. Just packed up and started for New York—walked right out to catch the 8:20 in to Boston. I suppose people will talk, but I can’t help that. You needn’t mention that there was any trouble—just say she’s gone on a long research trip.
     “She’s probably going to stay with one of her horrible groups of devotees. I hope she’ll go west and get a divorce—anyhow, I’ve made her promise to keep away and let me alone. It was horrible, Dan—she was stealing my body—crowding me out—making a prisoner of me. I laid low and pretended to let her do it, but I had to be on the watch. I could plan if I was careful, for she can’t read my mind literally, or in detail. All she could read of my planning was a sort of general mood of rebellion—and she always thought I was helpless. Never thought I could get the best of her . . . but I had a spell or two that worked.”
...

“I had to save myself—I had to, Dan! She’d have got me for good at Hallowmass—they hold a Sabbat up there beyond Chesuncook, and the sacrifice would have clinched things. She’d have got me for good . . . she’d have been I, and I’d have been she . . . forever . . . too late. . . . My body’d have been hers for good. . . . She’d have been a man, and fully human, just as she wanted to be. . . . I suppose she’d have put me out of the way—killed her own ex-body with me in it, damn her, just as she did before—just as she, he, or it did before. . . .”

- The Thing on the Doorstep, part V