Help with a BBEG

[Azoth]

I am looking to throw my players for a loop. So far in the campaign they have been fighting monsters true to the word, or if they have killed a humanoid it was purely in self defense. So for the next arc, I want to have them faced with a purely Human BBEG that is evil is the most real sense. Not the puppy kicking, blow up the world kind of evil, but pragmatic evil.

The kind of guy who can put people in a situation to make the evil choice by making it practical. Think Hans Landa from Inglorious Bastards kind of evil. I am not overly worried about his combat ability, because I plan on making the challenge actually getting to him. I would like to keep spellcasting to a minimum as well. Showing that it is his silver tongue that has gotten him where he is and has gotten him so many followers.

Knowing my players, he will get the chance to speak before being killed. So, I intend to have him offer them seats at his table as well as refreshments while he talks. The challenge for them, will be to resist his reasoning and the thought of killing a human being who is not hostile towards them in cold blood. I want the mind game to mess with them more than anything.

[Waker]

You could try playing the Joker Bard build seen here for an effective speaker. What he lacks in sheer magical might he makes up for in being unpredictable and persuasive.

[daemonaetea]

Just typing up the first thing that comes to mind...

How about having the man be the mayor of a town? The town is in a desert/region going through famine/some other place which has a pressing need for a resource. This man has secured this resource, but the ones he's getting it from want something very specific in turn - virgin sacrifices/young slaves/organs. The what's needed and what's given can be pretty much anything. The important thing is that the ones providing it are the only possible choice, and that without it the entire town will die.

As for the difficulty of reaching him? Why, the entire town is protecting their beloved mayor, who has gamely kept their town alive in these trying circumstances.

If you want to go with the nicer option, have the party discover a way to keep the town alive without the evil, possibly that the mayor knew about all along. For the darker solution, have them stopping the mayor really destroying the town.