He’s not named, but the dude in the hat who kills the monster named Grottu is Ulysses Bloodstone. He also appears, unnamed, in Tales of Suspense #9.
He’ll get some solo adventures in Rampaging Hulk magazine in the ’70s, but his biggest overall contribution is being the father to Elsa Bloodstone, the monster hunter.
I’m just including these two issues for the sake of completeness. I don’t even own them–I’ve just read about them and the picture above from the ‘net.