Dr. Yi Suchong M.D. was a leading medical researcher in Rapture studying ADAM and its uses to create Plasmids and alter brain function, as well as creating the Little Sisters and Big Daddies. Usually referring to himself in the third person, Suchong was an egomaniacal opportunist, using even tragic events such as war to his own benefit. He conformed perfectly to Rapture's society and worked simply for the highest bidder.