Umbridge and Firenze became a couple because Umbridge was the only human that could survive intercourse with a centaur. Because all of the female centaurs had died out it is now Umbridge's job to repopulate the centaur race. At the Leakycon in 2011 Jim Povlovo who plays Firenze talks about his realationship with Umbridge. He said that she has proved to be more powerful and bloodthirsty then any other centaur. He said that because of her, their centaur tribe now rules the forbidden forest. Jim also mentioned that Umbridge has magically grown a horse half and is now know as Motaro.