Reginald Lannister

Reginald Lannister is a minor character in the second season. He is played by Patrick Fitzsymons and debuts in "The Ghost of Harrenhal." Reginald Lannister is a distant relative of Lord Tywin Lannister, belonging to a cadet branch of House Lannister established on the city of Lannisport.

Background
Reginald Lannister fights for Lord Tywin in the War of the Five Kings. However, Tywin has made him an officer in the Westerlands army due to his name, and actually views him with contempt. He's married.

In the books
In the books, there is no character by the name of Reginald Lannister. Among Lord Tywin's bannermen at Harrenhal there's actually no member of House Lannister.