Mask - The Trickster God

Mask is a complex deity who can be perceived as Neutral Evil, but that depends on which side of the stick you're on...better pinning them down under Chaotic neutral. Not concerned the side they are on as long as it involves intrigue and obfuscation. They are associated with Shar as they somewhat share the portfolio of Shadows, though Mask to a lesser degree. It is however unknown as to why she would share it with them freely.
If Mask has someone to whom they diametrically opposed, it would be Oghma, who is the God of Knowledge. Mask enjoys secrets and obfuscation and finds them entertaining. 
His followers might be Clerics, Rogues, or the Rare Warlock.
Dogma: Ownership is 9/10 of that of what is right. and ownership is defined as possession.   The world belongs to those who are quick, smooth tongued, and the light fingered. Stealth and weariness are virtues. wealth rightfully belongs to those who can acquire it. Honesty is for fools but apparent honesty is valuable. Steal only what is vital, not everything at hand. make every truth seem plausible. Never lie when you can tell the truth, but leave a mistaken impression. Manipulation is better than force.