These lines are the heading to "In the House of Suddhoo" in PLain Tales from the Hills (1888); collected in Definitive Verse as a Chapter Heading, and in subsequent collections.
churel the particularly malignant ghost of a woman who has died in child-bed see Kim (p.197, line 8)/
ghoul Arabic ghul Persian ghol, a goblin or man-devouring demon. [Hobson-Jobson].
Djinn a class of spirits in Mohammedan mythology, formed of fire in various shapes, sometimes as huge men of portentous ugliness, see "How the Camel got his Hump" in Just So Stories.
Powers of Darkness A phrase much used by Mulvaney in the soldier stories – an echo of Col. 1:12,13:
Giving thanks unto the Father, who has made us fit to be partakers of the inheritance of the saints in light. For he has delivered us from the power of darkness, and has translated us into the kingdom of his dear Son.
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