Heart-Eater

Matagael Caltalor paced. 

The love potion had failed. 

Thirty gold streka gone. Matagael snarled and swept a stack of books and parchments off his work table, sending them crashing the floor. He could imagine the weight and heft of the gold coins, struck with the seal of Great Streka with its crossed wands and hermetic seal. 

It was the third such failure. He had spent nearly a year's earnings chasing a love potion that would put fire back in his own heart.

Haleara looked up hopefully, she longed for her husband to come back into her life like the beast he had once been. 

"I'm sorry, the potion should have taken effect by now. I feel nothing."

"We can see that the alchemists suffer for this failure," Haleara said. Matagael shook his head, slowly, defeated.

"There is no reason, it isn't their fault," he said. 

In the shadows of the room, the eyes of the Heart-Eater shimmered. Matagael was almost dry, almost no emotion or passion left in him. It turned its gaze towards Haleara, and the feast of anger, frustration, and desire close to boiling over in the woman.

The Heart-Eater 

Heart-Eaters are a form of astral or ethereal vampire, incorporeal creatures that are neither alive nor dead, and feed on the emotions rather than blood. The creature itself follows its prey at a distance, and bonds with them when they are asleep. During this sleep, they draw off the emotional energy of the host. 

In populated areas, a Heart-Eater can feed for a long time with no ill-effect. One such creature can attach itself to a single person for a few days, or a few weeks, with no lasting damage. After a few days the host might seem subdued, emotionally unavailable. On occasion a Heart-Eater will attach itself to a person and drain them until they are a sunken eyed shell, moving through life like an automaton. They might demonstrate symptoms of depression, and eventually could become suicidal, or be harmed by attempts to remedy their emotional state: heavy drinking, drug and potion abuse, seeking danger to excite them. 

There are two situations that will lead to a heart-eater riding a host until they perish, starvation situations or unique individuals. In a situation where the local population is diminished or isolated, a heart eater will spread it's feeding until it feels fear, and then will one by one sate the creature until it escapes to a populated area, or is forced into dormancy. Unique individuals are generally those with divine blood, arcane skill or innate magic ability, and so forth. This is a dangerous game for the Heart-Eater, as these individuals might have magic abilities that allow them to perceive and interact with non-corporeal beings. As such, even being insubstantial and invisible, they will go to great lengths to avoid notice. 

Threat Matrix

The heart-eater can 'inject' emotional venom into a target. This can send the target into a rage or a frenzy, usually following whatever the concentrated dose of emotion would dictate. This is something the creature can do, but is loathe to, as it is pumping its emotional derived essence into another creature. Some Heart-Eaters will do this, and then fall on the host while they are in the midst of their emotional fury and attempt to ravage them, an act that generally burns the host out and they die of heart failure. Some will do this to push a host to suicide and ride the emotional wreck like a heroin junkie. Each Heart-Eater will have their own feeding preferences. 

When threatened, a Heart-Eater can use this power to send decoys and distractions towards a foe that is aware of it, pursuing it. Thus, a canny mage might find himself caught up in a violent brawl because the Heart-eater stirred up violent emotions, triggering hatred and racism towards the mage in some form or fashion.

Use:

Heart-Eaters aren't stand up and fight foes, they are emotional parasites that have to be fought with spell and wards. They are a foe intended for a paranoia based game, something more suited to survival horror, or similar. 

Appearance:

A Heart-Eater resembled a shriveled and mummified pangolin or armadillo, a bony carapace wrapped around a shrivel body. The eyes are small, sunken, but shine with intensity.