In the Perlesvaus tradition (c. 1200-1210), the Perilous Chapel and its associated cemetery presented one of the most dangerous adventures in Arthurian literature. Perceval was required to brave the horrors of the haunted grounds to retrieve the shroud that had covered the body of Jesus Christ-a relic essential to the Grail Quest. The cemetery teemed with supernatural dangers: reanimated corpses, ghostly apparitions, and the demon guardian itself, a being of pure malevolence that attacked any knight lacking sufficient spiritual protection. Perceval's sister Dandrane also made a pilgrimage to the Perilous Chapel to retrieve a piece of the holy shroud, demonstrating that the quest was not limited to male knights but extended to all who sought the Grail with pure intention. The chapel's role in Perlesvaus reflects that romance's unique emphasis on Eucharistic symbolism and the literal relics of Christ's passion.

Malory's Le Morte d'Arthur presents the most detailed account of the Perilous Chapel and its demonic guardian. In this version, the chapel is heavily guarded and ruled by Hellawes the Sorceress, lady of the Castle Nygramous, who adds a layer of feminine dark magic to the demonic threat. The specific adventure that draws Lancelot to the chapel involves Sir Meliot de Logres, who had killed Sir Gylbert the Bastard in combat. Gylbert's lover, a witch, cast a spell upon Meliot ensuring that his wounds would never heal unless some brave knight entered the Perilous Chapel, retrieved a bloody sword from within, and used it together with a piece of bloody cloth wrapping Gylbert's corpse to search the wounds. Lancelot, encountering the suffering Meliot, vowed to undertake this perilous task.

Lancelot's journey to the Perilous Chapel tested his courage against supernatural terror. He followed a black hound (brachet) tracking a trail of blood across an old, feeble bridge into the haunted manor where Gylbert's body lay wrapped in its bloody shroud, with his grieving widow beside him. Continuing into the Perilous Chapel, Lancelot confronted its guardian demon in mortal combat. The creature attacked with hellish ferocity, but Lancelot's unmatched martial prowess-honed through countless earthly combats-prevailed against this supernatural foe. He retrieved the bloody sword and cloth, returned to Meliot, and healed the knight's wounds, demonstrating that even a knight barred from achieving the Grail by his sins with Guinevere could perform acts of redemptive courage against demonic evil.

The Demon of the Perilous Chapel operates within Arthurian symbolism as the guardian of threshold spaces-places between the earthly and divine where only the worthy may pass. Its Christian context is unmistakable: the demon defends a chapel, a cemetery, and holy relics associated with Christ's burial. Its defeat required not merely physical courage but spiritual resilience; knights who approached it with unconfessed sin or fearful hearts were destroyed. The chapel's "perilous" nature thus reflected the medieval Christian understanding that approaching the sacred while in a state of sin brought damnation rather than salvation. Gawain and Hector saw visions of their own unworthiness; Lancelot, though barred from the Grail itself, could still defeat the demon through sheer martial virtue. The Demon of the Perilous Chapel thus stands as a liminal monster, marking the boundary between earthly chivalry and divine grace.