Seething Spirit

Hatred so powerful it lives beyond the grave-this sentiment animates the ephemeral crimson apparitions known as seething spirits. Single-minded in nature, they stoke the fires of anger and hate, capable of planning and strategy, but the one thing beyond their grasp is personal growth. Though similar to ghosts, seething spirits retain much less of their former living selves. Most of their soul has moved on, and only the fury remains. There's no way to set a seething spirit to rest: only violence can destroy it.

By possessing a creature and nurturing the seeds of resentment and rage already within its mind, a seething spirit can greatly alter the host's behavior and personality. When broached about such changes, a host might claim they're just finally "telling it like it is." Because a seething spirit can't voluntarily end its possession, it's essentially one with its victim until the victim's rage results in death. A seething spirit doesn't take pleasure in this death-they rapidly move on in search of a new rageful host.