Sea monsters and their inspiration: serpents, mermaids, the kraken and more
nhm.ac.uk
nhm.ac.uk
I also wonder about the role humans played in that people were probably smaller on average, in smaller boats etc. The same squid is going to be more of a threat if everyone is smaller, on what today would be considered a smaller boat, and those are the limits of the human world.
[1] https://www.nhm.ac.uk/discover/animals-named-after-mythologi...
I's also interesting that the protagonist Sklar Hast has a Scandinavian origin name but, that also the Kraken (Kragen in the book) originated from Scandinavian folklore.
Well worth the read.