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I need a name, description, and and some kind of weapon or power.

A place I like to go and fool around with character ideas is http://www.seventhsanctum.com/ just for fun and to get my mind thinking.
Picking a name, I usually look at baby name sites for ones that sound like they'd fit, or try and match the meaning with an important trait or characteristic.

What sort of habits does your character have? ex: Does he go for walks in the sun or sit inside to plot up his schemes? In either case his skin and muscle ton vary.
Where is he from? Each culture has their own clothing and hairstyles. (He should fit his surroundings, or is he a rebel and goes against what is the "norm" for where he lives?) It will also help you narrow down colors for hair, skin, and eyes.
What sort of presence do you want him to have? Do you want him to be noticed when he walks into a room, or do people over look him?

Hope this helps!

The way I have been plotting out my characters lately is really helpful to me...maybe it could help you as well.

You need to be able to develop your characters throughout the story, even if they are the antagonist.

What is he fighting for? What is he fighting against?

Is there a particular scene you can imagine your antagonist in?

This works mainly for protagonists, but I think it could be adapted either way.

You need to be able to give them emotions, actions...I've tried basing them off of their name before and it doesn't always help.

Also, I would start with appearance and work into personality. My names usually come last. Your character needs to embody what the true antagonist force in your story is.

I hope this was actually helpful instead of sounding like babbling.