Who is Lord Tywin Baratheon from A Clash of Kings and what is their importance?

Tyrion Lannister is the son of Tywin Lannister, uncle of King Joffrey, Tommen, and Myrcella, and the brother of Jaime and Cersei Lannister. Tyrion is sent by Tywin to be King Joffrey's advisor, the Hand of the King.