Already free from the mortal world once, returning to undeath has granted the Forsaken complete immunity to fear and charm/mind control effects.

As an undead, sleep is not needed. During long rests can sit/lay still to recover health. 

As an undead damage taken from an kind of holy attack or ability is increased, while reducing necrotic/shadow damage.

Grants darkvision

Does not need to eat or drink as a normal mortal, but can instead consume the flesh of humanoid corpses to regain health. At the cost of nearby humanoids being disgusted.

Most folks don't take too kindly to zombies, meaning that most people in town areas will fear or hate the Forsaken in varying degrees, from simply being rude to outright attacking them on sight.