Who is Mr. Tulkinghorn from Bleak House and what is their importance?

Mr. Tulkinghorn is a lawyer, who is heavily involved in the ongoing Jarndyce and Jarndyce case. He is devious and manipulative. He is also great at accumulating the secrets of others and using those secrets against them. In the end, Tulkinghorn is murdered by Hortense, Lady Dedlock's former maid.