Revenant

Revenants are obsessed, undead stalkers who arise from their own murders and are driven by only one thing: revenge against their killers. The common wisdom is that revenants arise only from individuals who have been utterly betrayed or abandoned to die a grueling death, but even then, such victims might not rise from their graves. In other cases, revenants might even rise from what might legitimately be considered an accident if the revenant doesn't understand the full circumstances of their demise. In such cases, it doesn't matter that the "murderer" may not have intended to kill, for revenants understands no pity and can never forgive. Revenants have little memory of their lives other than anything they might need to recall in order to achieve their goal of vengeance.