I finally met the Hunter of Heroes, what a cool looking beastie! He decided to attack my Stone-Sword wielding Gargoyle. I must have been super-lucky, the Garg's MR is only 12, but all he got hit with was the Astral Fetters and Cursed Luck. Maybe "Lifeless" is protection from "Consume Soul"? It's weird that he didn't get horror marked from the Hooks, maybe they have to do damage to cause a horror mark? The Garg is wearing Monolith Armor. He's not horror marked at all, it's his position in the HoF plus AC that attracted Rarku I think.
The Gargoyle even managed to escape the fetters and turn Rarku into a statue.