Power vs. Vulnerability?

I'd say that the burden that leaves you destined for doom much more tragic than anything else. As you said, no weapon could cut Grendel and that makes him nearly invincible, so the humans have no choice but to die. There is nothing they can do to save themselves, and death is no longer a matter of if but when. But I don't think that his invincibility prevents him from communication. In fact, the only reason he was able to talk to Unsferth at all was because Unsferth couldn't leave a scratch on him. Since Grendel can no longer be hurt by men, he should make the attempt to communicate better since he has all the time in the world. That's exactly what he did with Unsferth when the warrior followed the monster back into his cave on page 90.

To me it seems as if the humans should have tried harder to create peace with the beast because it was apparent that they were going to lose no matter what. The imminent certainty of failure should spark the humans to try to reason with the beast especially after Unsferth understands that Grendel is capable of communication. The two parties have a lot of common ground, one of which is the inability to communicate.