Most ominous are the masses of dense, desultory, menacing willows, which "moved of their own will as though alive, and they touched, by some incalculable method, my own keen sense of the horrible".
His friend, known only as "the Swede," is early on characterized as being solid, pragmatic and not at all fanciful, a fact which makes it more chilling when later he is able to clearly perceive supernatural danger.
Shortly after landing their canoe for the evening on a sandy island near Bratislava in the Dunajské luhy Protected Landscape Area of Austria-Hungary,[2] the narrator reflects on the river's potency, human qualities, and his own will: Sleepy at first, but later developing violent desires as it became conscious of its deep soul, it rolled, like some huge fluid being, through all the countries we had passed, holding our little craft on its mighty shoulders, playing roughly with us sometimes, yet always friendly and well-meaning, till at length we had come inevitably to regard it as a Great Personage.Blackwood also specifically characterizes the silvery, windblown willows as sinister: And, apart quite from the elements, the willows connected themselves subtly with my malaise, attacking the mind insidiously somehow by reason of their vast numbers, and contriving in some way or other to represent to the imagination a new and mighty power, a power, moreover, not altogether friendly to us.At one point, the two men see a traveler in his "flat-bottomed boat".
During the night, mysterious forces emerge from within the forest, including terrifying huge dark shapes launching from the willow branches upward into the sky, tapping sounds outside their tent, shifting gong-like noises, bizarre shadows, a feeling that the atmosphere has grown heavy and is crushing them, and the appearance that the willows have menacingly changed position, crowding toward the tent.
The precise nature of the mysterious entities in "The Willows" is unclear, and they appear at times malevolent or treacherous, while at times simply mystical and almost divine: "a new order of experience, and in the true sense of the word unearthly", and a world "where great things go on unceasingly...vast purposes...that deal directly with the soul, and not indirectly with mere expressions of the soul".