@tyrion85, @Abits, see @KillerRabbit's post. The short of it is that you cannot just change a part of the Realms setting into an evil place. Your character can be evil. But no part of the world around you is going to become or represent evil. The FR setting is a GOOD setting. It is a setting where good prevails over evil. ALWAYS. That is the very essence of the FR setting, and WotC will stand by that, canon or not.
Originally Posted by Vhaldez
The evil path gives you less benefits than the good path.

This is a very accurate portrayal of the FR setting. The moral of pretty much every novel written using the FR setting is essentially that evil does not pay, and that even when the evil side "wins," the win is temporary and will soon be reversed by the good side. Heck, the big criticism some people have of the setting is precisely that it is a "goody-two-shoes" setting. For evil-liking people, this criticism makes sense. For someone like me, I love the setting exactly for its goody-two-shoes nature.