Hargrimm the Bleak is a skeleton priest in the Dead Nations. He greets anyone who enters the Silent King's domain with a demand for them to be made prisoners until they die and can be raised as undead, at which point they become free citizens of the Dead Nations.
After initially submitting to the will of the Undead, TNO can speak to Hargrimm, who has a lot of information to give about his society.
Hargrimm reveals that only with an order from the Silent King could he allow the Nameless One and his party to leave. However, he refuses to grant TNO an audience, at least not until he has proven himself to him.
Telling Hargrimm about Soego, after his fate is sealed grants 3750 XP, and gets the skeleton to trust TNO a little more.
After that, he can be asked again for an audience with the Silent King. Now he is more agreeable and if asked what TNO can do, he will give him a task: Killing some Cranium Rats that have made their way into the Dead Nations. A cluster of them (enough that they can cast spells) can be found in the collapsed hallway blocked by rubble (X=550 Y=2000).
Returning to Hargrimm after dispatching the rats grants 3750 XP and he will free TNO for a further 7500 XP.