main-(MAIN) (adj)1. of highest importance or the common part (mainland) The main point -mainly, main
… a.k.a. s/he who does not change. The villain is the character who you plan and write, no detours! (Meaning that you don’t plan some complex scene in which your main antagonist begs for mercy and becomes one of the “good guys” of the story-unless you want to disappoint your readers. I love hating villains, and, honestly, I’ll put the book in which the above happens down in disgust as I find it very difficult to process that the main antagonist is no longer evil and I… well, you get the point.)
See here to read more on villains.
Do you get the point?
Good. Make the villain’s assistant the traitor.
Now give them a reason to betray.
If you’ve already sent the book in which the above happens out to publishers and it’s published (or in the pile, waiting to be published) tough luck on revising it.
Are you writing a book? Well… If you’re writing a book, you haven’t introduced your villain yet, and are still planning the villain out, you have hope.
About the editing-the-scene-so-the-assistant-betrays-the-villain-instead-of-the-villain-betraying-the-assistant part.
If you’ve made a big deal about, like “the green haired villain will set aside control of the kingdom of her home to help the brave souls who dared intrude upon her kingdom of wonderfully bright, and shiny mowed lawns” and your main antagonist has green hair (and is the only one with it), then change “green” to the color of the assistant’s hair.”The blond haired villain will set aside control of the kingdom of her home to help the brave souls who dared intrude upon her kingdom of wonderfully bright. and shiny mowed lawns” could be there instead. Or brown hair, black hair, red hair, whatever.
Now that you have all this down, you should write her/him a scene.
Maybe five pages, not much. When you’re finished, read it over and edit and revise it. Finally, give it to someone who’s opinion you trust. Ask them what was good and what was bad. Etc.
Maybe write another page. Keep adding until (maybe) you have a whole chapter.
I once read a book in whicvh the advice I advised in this post was misused. Guess they didn’t listen to me!