riddle - The strange story of Lord Lefthide

Lord Lefthide was found dead in his mansion, to what it would seem of a heart attack. But it appears that moments before his death, he was writing some uncanny childish story. He was indeed found dead at his desk with a pen in his hand and the following note in front of him:

"That wretch ! He still watches for me", the bunny says.
Old, browsing the site, the patient hunter embraces the shadows
"Nobody is immortal, especially not you, bunny!"

Fearless little bunny, he nonetheless hides beneath a shrubbery.
"Great human, hunting's forbidden! Drop your searches!", he cries,
"The tide is rising, stop this madness at once!"

"What an insanity!", says the lurking man, "The sea is set one mile away!"
He stops, most of his body is moistening.
"Indeed, in water I dwell..."

What truly killed Lord Lefthide ?

Hint 1

The three verses are separated for a reason, and they all have a common point.

Hint 2

The name of the Lord is definitely a red herring, sorry for that. Still, it's an interesting anagram of someone's name linked to this puzzle.

Hint 3

The answer to A most curious story about something stolen

Answer

Answer

Clued in by @Gustavo-Gabriel we know that Lefthide is an anagram for Hetfield, the last name of James Hetfield, the songwriter for the band Metallica. The suspect is confirmed with the lyrics of the Metallica song “The Thing That Should Not Be”. The main chorus of the song holds the similarities:

Fearless wretch
Insanity
He watches

Lurking beneath the sea
Great old one
Forbidden site
He searches
Hunter of the shadows is rising
Immortal
In madness you dwell

Indeed if we use the third hint, we find that each word comes from reading each third word in successive paragraphs going from the 2nd, then 1st, then 3rd paragraph, and repeating.

Theories
I’ve tried to look at different patterns in the remaining words - nothing so far, but there may be some other steganography relating to the common point from the first hint. Perhaps we’re supposed to look for “the thing that should not be”.

The song is strongly influenced by the stories of H.P. Lovecraft an American horror fiction writer. The answer could be the same way that Lovecraft died - Cancer of the small intestine and malnutrition.

Another possibility would be to look more in depth into the meaning behind the lyrics or to find more clues in Lovecraft’s stories that could lead to a solution. For an example possible lead, a quote from Wikipedia about Lovecraft’s novel The Call of Cthulhu (which is featured heavily in the song) reads “After finishing the manuscript, Thurston realizes he is now a target of Cthulhu's worshippers”, although I don’t think this is correct.