Who is Malgras from The Masterpiece and what is their importance?

Malgras is an art dealer who knows nothing about art but has an eye for profit. He is described as scruffy and a crafty businessman. Over time, he manages to get excellent paintings from Claude and other local artists at ridiculously low prices. Malgras can sense of when an artist is in desperate need of money and has a way of feigning disinterest in the very paintings he ends up buying. In other words..... he is a master manipulator.