Genderless

Villains whose genders are unknown or cannot be classed into normal genders.

Some of them can still be identifiable as male or female, but not physically or mentally built as such. This is because their biology, or lack thereof, is alien, but humans tend to need and use gender references and identity, which is why cars and ships are often referred to as "she." Others are deliberately ambiguous as a means to unnerve a bigoted audience.