Speak to Warden Nork Bloodfrenzy.
While you have done much to secure our foothold in these frozen wastes, other dangers still lurk in the shadows. I want you to assist Warden Nork Bloodfrenzy, stationed at the internment camp just outside and immediately southeast of Warsong Hold. Seek him out and offer your assistance for prisoner transport and exchange.
You are dismissed, <name>.
Prisoners? These aren't prisoners. They're cowardly dogs! Just look at 'em. Did you know that without exception, every single one of these yellow-bellied "soldiers" came to our gates and surrendered their arms and armor?
From what we've been able to gather, these men and women are discharged and sent back to their homes if captured by us.