A novel by the late John Gardner, written in 1971.
We all know by now that it's narrated by the Monster himself. Like all monsters, you and me and everybody (ohhh, that's so deep, ha ha ha), he feels sorely put-upon and quite justified in what he does. Unlike many of you, he's comfortable with the idea that he's been sent to punish the human race. Nevertheless, he wouldn't mind being loved. The humans enrage him, but they fascinate him as well. Sometimes he eats them, and sometimes he just spies on them. He worries about them a lot. He's lonely.
His family situation is problematic: His mother is devoted to him, but unable to communicate. He lives with her in a cave full of offal, beneath a lake. His father is out of the picture, unmentioned. The closest thing to a father figure in his life is the Dragon, a miserable, fatalistic nihilist (atesh tells me (very politely!) that I'm on crack and the Dragon's an existentialist. Since I get the impression that atesh (unlike me) actually knows the material, I'd advise you to take his word for it) who scares the living crap out of the poor little monster.
Grendel lives in a world of inexorables: From where he sits, the Dragon is raw Power. He stands blinking at the Dragon like a brainless rabbit. In turn, the thanes are helpless when Grendel roars into the meadhall to eat them. It's their fate. They can't win. Unferth, their greatest hero, is destroyed when Grendel whimsically decides not to kill him: Nobody even gets to choose for himself to die bravely, really. Then the Danes arrive. It is in their nature to win. It is their fate, as it was the local thanes' fate to lose, and Hrothgar's fate to sit there watching. Ultimately, Grendel's fate is also to lose. The Dragon is fated to lose as well, but he knows it and he's well past caring. He's outside time and he just doesn't give a damn, really. He lives to satisfy his immediate desires: That intellect of his is really just an impotent passenger riding on the back of a senseless brute lust for gold.
You might say that Grendel and Hrothgar are the only real people in the book. The other humans are uninteresting because they're unreflective (yes, I do believe that silly bard is unreflective). They march stupidly to their doom. There's nothing happening inside. Beowulf is exciting and he's got that whole Shane thing going on, but he's a brute. The Dragon is uninteresting because he's a too-obvious literary device. Gardner had a weakness for those, sometimes: Too much time spent in too many writing workshops. He just missed greatness. In the end, he marched stupidly into a tree on his motorcycle, still not as famous as Pynchon.
All this fatalism, of course, is perfectly appropriate for the time the epic describes. You can't really get inside the heads of people so far off and as stuck in their own context as we are in ours, and anyway, a lot of the dramatic power of the novel grows out of the anachronisms and contrasts. You need the feel of the epic there for it all to work, and epic poems aren't long on introspection. It's in their nature.
Grendel and Hrothgar are real because they stop and think about it, and they don't much like it. They want more than to be chained to the wheel. Hrothgar is too stoical to like very much and Grendel wallows in self-pity, but at least they're human.
"'Poor Grendel's had an accident...', I whisper. 'So may you all.'"
It's a beautiful book and that's the only excuse it needs. Whatever else you may say about it all, the man could surely write.
 Furthermore, nihilism is too easy. Anybody can do it, and the only grown-ups it appeals to are the ones who should be on medication (and of course sleazy academics who notice how all those poses pull the coeds, not that I'm jealous or anything).