MIT Mystery Hunt 2020/The Holy Cup of the Raven-God

The Holy Cup of the Raven-God is a puzzle from the round of the 2020 MIT Mystery Hunt.

Puzzle Elements
Text-Heavy - The puzzle is stated in the flavortext to be a poem, although it is rather more like prose in construction. Each paragraph consists of one long non-sensical line, then states below it a number of familial relations.

Flavortext - ''While wandering the park, you encounter the balloon seller, in the guise of an old, cloaked, man. He fixes you with one eye and utters this poem.''

Knowledge Required (Poetry) - The first line in each paragraph is a sentence containing nested kennings (a kind of Norse wordplay that obliquely refers to nouns by a phrase using two others). The referents of a kenning can be found by searching a website such as that of the Skaldic Project.

Identification (History) - Simplifying the kenning all the way down results in a phrase that identifies a specific historical Viking. The familial relations below the sentence can then be identified. As an example, take the first kenning, reducing down to "The serpent-tongue who dueled, in the last of its kind, with the raven and found death in it". A Wikipedia search yields Gunnlaugr ormstunga, where "ormstunga" is the "serpent-tongue"; he dueled Hrafn (Raven) Önundarson in the last hólmganga (duel) allowed in Iceland. Referencing his saga yields THORGERD as his mother's mother, HELGA as his true love, and HERMUND as his brother.

Knowledge Required (Mythology) - Associated with each relation is a phrase making reference to Norse mythology. Each resolves down to a number...

Indexing - ...that can then index into the names of each relation.

Final Clue Phrase - The phrase obtained this way is THE DOG STAR IS LOKI'S BLANK, a clue for the final answer.