I didn't mean to insinuate that it was plagiarism or anything like that; this is likely just an example of how culture teaches us that certain characteristics fit archetypes. It's like how the
El
dra
zi
resemble the
Ogdru Jahad from
Hellboy, but rather than the former copying the latter, they were both inspired by the "Great Old Ones" from the
Cthulhu Mythos.
I guess there's just something about extra-long forearms that screams "I'm a being of great, dark power!"