Biter

Biter is a character in Game of Thrones. He debuts in the second season and is played by Gerard Jordan.

Biter is a criminal from King's Landing. Along with Rorge and Jaqen H'ghar, he was fished out of the dungeons by Yoren and forcibly recruited into the Night's Watch. He is accompanying the rest of Yoren's new recruits northwards to the Wall.

In the books
In the Song of Ice and Fire novels, Biter was a mindless thug from King's Landing, an associate of Rorge. Rorge ran several fighting pits where dogs and bears would fight one another and also people. Biter fought in the pits and developed a reputation for savage cruelty. He has no tongue and only speaks through hisses. His teeth have been filed to points.

Behind the scenes
Fans have speculated that the three prisoners in Yoren's wagon in the final episode of the first season of the series were meant to be Rorge, Biter and (in a cloak with his face hidden) Jaqen H'ghar. However, these three roles were played by extras, with full-time actors for the roles not hired until filming of Season 2 was underway. Whether these were indeed the same characters and have been recast, or another explanation will be found for the discrepency, is unclear.