Grendel

Here's my vision of Grendel, the humanoid monster (was he an ogre, a troll, a giant, a berserker, or a devolved human, it remains unclear) who opposed the legendary warrior Beowulf in the eponymous Anglo-Saxon poem, written between 975 and 1025 ! He lived in a swamp near King Hrothgar of Denmark's mead-hall, and for 12 years, he constantly raided it, angered by the noise which came from it every night. Since no weapon could damage his tough skin, the King's men were powerless against the monster's rage.
When the warrior Beowulf came to Hrothgar's court, he faced Grendel, and after a long fight, he mortally wounded him by tearing one of his arms apart with his superhuman strength. The monster then returned to his damp domain to die near his mother, who would later oppose her son's murderer. Some sources (post-christianization ones it seems), identify Grendel and his mother to descendants of Cain, the first murderer in the Bible.

I chose to cover his body with bony plates reminiscent of both armadillos and crocodilians, exploiting the tough skin part ! In my mind, he is some sort of "devolved" human whose organism, after countless generations living like an animal in harsh environments (and maybe with two or three matings with non-human creatures to make it worse !), developed a superhuman stature and strength, sharp claws and fangs, in addition to his hard skin.