From Monkey Island wiki
Mister Santiago is a supporting character in Escape from Monkey Island. He plays chess on the Lucre Island docks with Señor Castaneda and enjoys taunting his partner about his unrequited love for Brittany the bank teller. He is tubby and has a large walrus-moustache. He seems to have a "fascination" for food which Guybrush uses to distract him from his chess game. When he and Castaneda get into a fight the latter begins using insults referring to his weight. These are regarded by Guybrush as some of the poorest insults he's ever heard.