Who is Nikolei Drevin from Ark Angel and what is their importance?

Nikolei Drevin is an extremely wealthy man, who is partnering with the British government on the Ark Angel project. He was once a high ranking officer in the KGB, and after the fall of the Soviet Union, Drevin used his contacts to do business with the Mafiya, Triad, and Yakuza. Drevin is the world's biggest criminal and seems proud of it.