Tycho Nestoris is a character in the fourth season. He is played by Mark Gatiss.
Biography
Tycho Nestoris is a representative of the Iron Bank of Braavos who has been sent to Westeros to negotiate payment of the Iron Throne's massive debts.
Season 4
In the books
In the A Song of Ice and Fire novels, Tycho Nestoris is described as a tall, gaunt stick of a man with long legs (a befitting form for a miserly banker). He has a gaunt face with a thin rope of a beard growing from his chin which hangs down to his waist.