During the time of the Battle of Fiara, Brok Dalingar of the Leonidar watchmen needed help to defeat a warrior's ghost near the old mine in the east of Liannon.

An undead threat

Recently the being had resurfaced and it had already slaughtered some adventurers who had tried to defeat it, so no one dared to go near it anymore. When the future Phoenix Bearer came to Liannon, Brok warned her of the ghost. But the rune warrior proceeded and attacked it.

A phantom has emerged from the old shafts and has been roaming around there ever since. Some people have already tried to drive it away. They all met their death! Perished by the ghost's rusty blade.
Brok Dalingar about the ghost

The ghost's remains

The ghost would dissipate but leave behind a ring and a sword. The sword was given to Brok as a proof of the ghost being defeated. The guard would hand over a small reward for having helped him getting rid of the ghost.

When showing the ring to Brok, he would say, that the rune warrior should talk to the merchant Ortah Gelfbeard. When doing so, this would start the quest From the Deep.

Lieutenant Fell demands the sword of the apparition as proof that the dangers has been averted. Should you defeat the ghost, bring it to me
— About Celen Fell's demands


Brok would give an advise when it is safe to fight the ghost. Usually he'd say that from level 5 onwards, it's safe. But if you've summoned your rune hero companion and completed Path to Eloni, then you should be strong enough to deal with him.