The Dark Gown is a strapless black dress with detached sleeves, a floor-length skirt, and a pair of thin belts around the middle, one of which has a small white buckle resembling a skull. Natalie's version also has a black collar that covers her neck.
The Dark Gown emphasizes its wearer's magic power, raising their Magic Attack and Magic Defense. It also boosts their Magic Attack further if they're hit by a powerful attack, and raises their resistance to Dark, Doom, and Instant Death.
Epic Battle Fantasy 4
Found in a chest in the Graybone Cemetery.