How do Sir Gawain and the Green Knight and morte d'Arthur convey a sense of the supernatural

Answer 1

In those stories, "a sense of the supernatural" will show up in the form of magic or any other type of not-normal behavior or occurrence.

Arthurian Legends - Myth Encyclopedia - Major Elements ...
A few of the knights—especially Gawain, Galahad, and Lancelot—emerge as distinct ... Supernatural beings and events abound in the Arthurian legends. ... the Arthurian legends in a volume called Le Morte D'Arthur (The Death of Arthur)
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