Final answer:
The term 'grendelis' is likely a typo and is unrelated to the description of Grendel's demise in the Old English epic poem Beowulf. The texts provided illustrate vivid descriptions of combat similar to the style of the poem, with Ethelred being a champion character akin to Beowulf.
Step-by-step explanation:
The question regards the term grendelis, which seems to be a misspelling or typo and is not used in the description of Grendel's end. The term Grendel is from the Old English epic poem Beowulf, in which Grendel is the name of a monstrous antagonist defeated by the hero Beowulf. The passage provided appears to be a pastiche or creative homage to classic English storytelling, featuring a champion named Ethelred who defeats a dragon, not unlike Beowulf's conquest of Grendel. Ethelred's confrontation is vividly described, imparting the final moments of the dragon in a grandiose and dramatic fashion, reminiscent of Old English epic narratives.
In conclusion, the question may refer to the literary character Grendel from the poem Beowulf, but the term grendelis itself does not appear in the description of Grendel's end or known Old English literature.