Blackhearts is the Stand of Jett Kessler. It grants her the ability to transform into a hulking, purple werewolf-like creature with vicious attack capabilities. Jett obtained Blackhearts after being shot with an Arrow by Enya. As a child, she spent the majority of her time in this form, leading many to mistakenly believe that Blackhearts was her true form during her time working for Dio. Unlike most stands, Blackhearts is visible even to non-Stand Users.

[ Transformation ] Blackhearts’ only ability to transform Jett into a monstrous form. Despite its simplicity, Blackhearts is powerful and resilient, being able to persist for long periods of time. Its claws and teeth are strong enough to cut through steel. Additionally, Jett can summon parts of her transformation over her human form, such as claws or a tail.

Blackhearts’ weakness is primarily its lack of special abilities. Against a long-range Stand or an enemy with non-physical attacks, Blackhearts is vulnerable.