Board Thread:Suggestions forum/@comment-29188552-20160805002620/@comment-25869554-20160807084010

"When the Erech Vale is added in Gondor (which I'm sure is planned), at night it should be inhabited by the usual Gondor NPCs but also 'dead hillmen' as they were said to haunt the area, they could also spawn rarely in the White Mountains. All other mobs would flee from them, knowing their peril. They would not be hit-able unless the player wields Anduril (obtainable from questing) in which case they can. If one is killed by Anduril, it would then follow you and act as a hired unit until dawn, when it would fade away."

- -from a suggestion of mine from ages ago

UPDATE: now that we know that the blackroot vale is being added, this biome could be used instead, as it is approximately the correct area.

In summary, they could possibly be 'hireable' but only by players who wield anduril, and they would only be hired and follow you around until dawn, or maybe until they had killed a certain (small) number of enemies.