I hate to break it to you, but I talked to Gray Catbird on PixarWiki about the PixarVillains site on those two characters and he says that you created it just so you put their antagonistic roles the way you want them to be. Those are his words, not mine. So it's not an official source after all because any one can edit it and say otherwise.
Darla Sherman is the SECONDARY antagonist, and Philip Sherman, or The Dentist is the main antagonist. I know because it says so on the Pixar Wiki site. Please be careful how you name your antagonist. If you're unsure what kind of antagonist a character is, DO NOT make such edits, okay?