Who is Mr. Devlin from Moon Over Manifest and what is their importance?

Mr. Devlin owns the local coal mine. He is described as a cruel man, who uses the cheap labor of immigrants in his mines and pays them in company store vouchers for their long hours of work. The people of Manifest are unhappy with work conditions and their pay, but they do not know how to stand up to Mr. Devlin to force a change. When it is discovered by the town that Mr. Devlin wants to buy the Widow Cane's property because the coal vein has turned and spreads under it, they decide to buy it first.