folk vs bloodline

folk and bloodline both are nouns.

Word	Noun	Adjective	Verb	Adverb
folk	Yes	No	No	No
bloodline	Yes	No	No	No

As nouns, bloodline is a hypernym of folk; that is, bloodline is a word with a broader meaning than folk:

folk (noun)	bloodline (noun)
the traditional and typically anonymous music that is an expression of the life of people in a community	ancestry of a purebred animal
people in general (often used in the plural)	the hereditary derivation of an individual
a social division of (usually preliterate) people
people descended from a common ancestor