Souless

Barovian's are made of flesh and blood. They are born, they live, they age, and they die. But not all of them—only about seven in every ten—have souls.
When a being with a soul dies in Barovia, that soul remains trapped in Strahd's domain until it is reincarnated in a newborn. It can take decades for a bodiless soul to find a host, and Barovians who share the same soul over generations tend to look alike. That is why Ireena Kolyana looks exactly like Strahd’s beloved Tatyana—both women were born with the same soul.
Strahd needs loyal subjects to feed his ego. Barovians without souls are empty shells created by his consciousness to fill out the local population. Although they are physically indistinguishable from Barovians with souls, they tend to be bereft of charm and imagination and to be more compliant and depressed than the others. 

Souless Characteristics: 

• Barovians without souls are maudlin folk who experience fear but neither laugh nor cry.
• They dress in drab clothing, whereas Barovians who have souls wear clothes with a splash of color or individuality.
• They are not effected by the Dream Pastries. 
• They do not cry when born.
• A Barovian women, soulless or not, can give birth. A child born in Barovia might have a soul even if one or both parents do not. Conversely, the child of two parents with souls isn’t certain to have a soul of its own. 
• All Vistani have souls
• Strahd periodically feeds on the blood of Barovians who have souls, but he can’t draw nourishment from the blood of the soulless. He can tell at a glance whether a Barovian has a soul or is merely a shell.
• If Strahd is defeated, the fog that surrounds Barovia fades away, allowing the inhabitants of the valley to leave if they wish. Only those who have souls, however, can truly leave this place. Soulless Barovians cease to exist as soon as they exit the valley.