Vincent was pure of heart and quite easy to prey on so Blake ate his soul and took over his body making him chicken out of carrying out his responsibility as the head of the family after his father fell sick thereby making him pour that burden onto his young daughter, Rosalie.
Rosalie was a fine young girl and though he longed to possess her youthful body and cause mayhem in the lives of men, she was just too young then and he was still enjoying the benefits that came with being the eldest son of the Valentina family so he put it on hold.
But just like the rest of the people he had possessed in the past, Vincent started to become weak and even his wife began to notice his unusualness so in order to keep her from suspecting, he turned her into a puppet that did whatever her husband said with no questions.
But even when he did that he forgot one very important variable, the smart and ambitious younger brother of Vincent, Walter.