*cue sinister music*
Writing Tip For Fellow Challenged, er Challengers.
The villain is evil, scary. Or maybe gets in the way of the protag.
OUT OF MY WAY, she says.
The reader wants to know why.
For truly sinister attributes, build your antagonist through the eyes of your protag. Don’t tell the reader what a badass the antag is. Prove it. Give the protag’s perception. Use her fear and anxiety to show the reader.