[talt]

I'm a beginning writer and I've got a problem with the main villain in my story. I've sorted out his motivation, his methods and why the protagonist is fighting him... but no matter how I look at it, this villain feels too similar to Palpatine, Darth Vader, Galbatorix, William Walker (Island in the Sea of Time) and Uncle (Mortal Engines Quartet).

Motivation: Uncle, fall in love with and are betrayed by a slave.

Method: William Walker, decides to build an empire by enslaving a more primitive group of people than him.

Supporters: Galbatorix, both collect together an assortment of allies, who help them in their rise to power.

Is this too derivate or am I getting wound up over nothing?

[Hresvelgr]

I think you're getting wound up over nothing. What you posted as "derivative" seems to be little more than a trope or basic idea, which is not bad in any way. As long as you keep them with a distinct personality and feel it's okay, and you should be able to do so relatively well at least. Also, people like William Walker aren't common villians I think, but then again I know little of the fictional Walker, only the real one who did something similar.