Nettie or Agnetta is the powerful voodoo priestess who created the Mask of Shadows and therefore controls the bearer of it – Michael LeRoi. Although she appears to be in her mid -20s, Nettie is in fact centuries old, her soul simply inhabiting the body of a young woman whom unfortunately became involved in Nettie's schemes.
Although incredibly powerful, Nettie cannot travel to Deadside, the realm of the dead, which is why she needs her "assistant" Jaunty and particularly the Shadow Man, a warrior that can cross between the worlds and fight battles in Deadside for her.
There is another side to the relationship that exists between Nettie and the Shadow Man. Shadow Man must get 'romantically involved' with Nettie (on a regular basis), giving his Shadow powers to her in order to sustain her youthful form.
Nettie is one of the two characters in the game that Mike or Shadow Man may 'talk' to. Her purpose in the game is to provide Mike with various items that unlock certain areas of the game (such as Luke's Teddy Bear, which allows Mike to travel to Deadside), as well as assisting his quest by giving him advice.
This advice is always based upon what she knows of the voodoo prophecy that the Shadow Man must fulfil. Having never really experienced Deadside in the way that Jaunty and the Shadow Man have, her speeches are therefore mystical allusions to be unraveled, rather than direct references and commands.