Answer:
Foil
Explanation:
Usually evil and tries to obstruct the main character.
No improvement to this sentence is necessary. It makes perfect sense on its own and sounds right. "Either" always takes an "or" else the word wouldn't make sense, as it's meant to contrast binary options.
eg.
I'm either going to eat food or drink water.
I can help you with your essay. i have done one like that before.