Speaking via The Source Blog, the scribe confirmed that five new villains will debut in the comic before its second arc wraps up.
Williams, who is working with W Haden Blackman and Amy Reeder on the project, also announced that the book's principal antagonist will be The Weeping Woman, a character inspired by Mexican folklore.
"We'll be focused on developing a rogues gallery for Batwoman, and leading that charge will be The Weeping Woman," said Williams. "It's very important for heroes to have strong villains. This is what helps define a hero's character.
"Right now Batwoman only has Alice for the most part. We're going to change that in a very big way. By the time the second arc wraps we'll have established no less than five new villains. We're excited over the impact this will have in the life of Batwoman, Kate Kane and the rest of the cast."
Batwoman #1 was originally slated for release in February, before the title's debut was moved to April. A new launch date of September 14 was recently confirmed by DC.