An old “wandering crow” of the Night’s Watch, Yoren is a ranger who is regularly sent out to scour the Seven Kingdoms for recruits to the Watch. He’s described as stooped and sinister, with a twisted shoulder and greasy, lice-ridden black hair and beard. His teeth are stained red from the sourleaf he’s constantly chewing. Though ill-favored, he’s tough and pragmatic, with years of experience behind him.
On the show, Yoren is rather less unsavoury in appearance as well as manners.
Yoren accompanies Tyrion Lannister on his journey from the Wall, including during his stop at Winterfell. At the Inn at the Crossroads, he is present as Catelyn Stark arrests Tyrion for the attempted murder of her son, Bran. He then continues on towards King’s Landing where he informs Ned of what his wife Catelyn has done. He then remains in King’s Landing to collect recruits for the Night’s Watch. When Ned is executed, he is present and grabs a hold of Arya who was hiding by the statue of Baelor. He cuts her hair and tells her that she’s now a boy and takes her with him north together with the other new recruits.