Who is Sangfroid from Liar's Poker: Rising Through the Wreckage on Wall Street and what is their importance?

Sangfroid is the nickname of the corporate bond speaker, who chills the trainees with intimidating questions about LIBOR and the TED spread. Mike names him Sangfroid for the ice water running in his veins. Sangfroid is one of the author's favorite traders for his brutally fair honest speech.