The old man [Odin] responded, "That is ill-advised. Dig several ditches for the
blood to run into; then you sit in one of them and thrust at the heart of the
worm [Fafnir the dragon]." [....] And when the serpent crawled over the pit,
Sigurd plunged the sword up over the left shoulder, so that it sank to the hilt.
Then Sigurd lept out of the ditch, and drew the sword out of the serpent.
His arms were all bloody to the shoulder. (Volsungs, trans. Jesse L. Byock)
Sitting in the ditch and letting the dragon's blood flow all over you? That sounds a bit like baptism to me. Then we go to Bodvar and Hott's fight with the dragon in Hrolf Kraki, in which Bodvar makes the cowardly Hott drink the blood and eat the heart of a dragon they have defeated, thus tranforming Hott into a courageous warrior.
In each of these, the dragon is clearly the bad guy: Fafnir is a transformed greedy human, and Bodvar's is a periodic scourge on the land. While both sagas are written (in their current form) during the Christian era, Hrolf Kraki is particularly Christian, with the narrator occasionally called Odin an "evil spirit" and whatnot.
So, what gives? It seems surprising to me that the iconography of a Satanic baptism and Satanic eucharist would be lost on these audiences. Is Sigurd perhaps being perceived as a Christ figure? Perhaps someone out there knows of some contempory reactions to one of these sagas.