In the same book, you have the "Kabal of the Obsidian Gauntlet" under the Dark Eldar section. This is described as "...a relic of arcane technology borne by their Archon, which has enabled many of these seemingly-suicidal raids to succeed, as he tears down ferrocrete bastions with its blackened grip."
So really, it is up to you. In the Hellbringer's case, what would be appropriate for the leader of a chaos warband? What sort of item would cause many of them to flock to one location? Obviously something of great importance, perhaps a weapon. Create some stats, or make it a rebranded power/force sword or something.
As for the Obsidian Gauntlet, I used just gave the gauntlet itself the stats of a power fist with some narrative wishy-washy stuff as extra abilities.
I've found the Enemies of the Imperium to not only be a good source of foes to fight, but an even better source of flavor, plot hooks, and locations to fight in. Much of it is only listed in name, which gives you the opportunity to fill in the details yourself.