Go to Brightwood - Westcliff Road and then follow the path turn left and you'll run into the demon door he's stubborn and he doesn't want to open at all.
First he'll be stuborn so you have to bug him like ten times
Then sonn he'll say he needs cheese so bring cheese with you when you see him
Next He'll tell you to get hairstyles Dreadlocks and Mutton Chops (if you already have these hairstyles before you give him cheese he'll say Mullet and Handle bar mustache) even if you are a woman.
You can get the Chops in the Beautification Factory in Bowerstone Market
And you can get the Dreadlocks from Curl up an Die in Bloodstone
After that he'll tell you to get some clothes
Yokel Hat from Clothing stall in Oakfield or Bandit Skull Cap in Fiendish fashions in Bloodstone
Noble top found in Pants! in Bowerstone Market or Corset from Bit of Skirt also in Bowerstone Market
Tart Skirt found in Fiendish Fashions in Bloodstone or Noble Trousers Found in Pants! In Bowerstone Market
and soon the demon door will give up and open for you