Will-o-the-Wisp

Encyclopedia Entry:
The wisp is an undead monster, the result from a fusion of demonic energy with the soul of a person that has died alone. Their bodies are comprised of raging flames of jealousy and they wear something like a cage around their body to hold the flames in. They are persistent, ferocious monsters.

Because of their loneliness and feelings of dissatisfaction, they are extremely jealous of the living; especially lovers or married couples that seem to be happy. When they see a man and woman in love, their flames increase in intensity and their ferocity increases even more. Due to this envy and jealousy of the living, there is always a darkly obscene passion swirling in their hearts. When they spot a man, they will smile gleefully as they assault and violate him.

Due to their origins, they have a sick obsession with men. When they capture a man they will shut him inside their own cage. The sex will be intense and relentless; they will adhere closely to a man's body and continue fondling him all day long without growing tired of it. When they kiss, they will continue sucking with their mouth and entwining their tongue with his as if to suck up every last drop of his saliva.

Once they have joined with a man, they hate the thought of his penis leaving their vagina, so they transform their cage to bind him, to ensure that he cannot escape. Once that happens, they will move their hips as if to cling to his penis and the man will continuously have his spirit energy squeezed and sucked out, all while he experiences pleasure of such a degree that he will be under the illusion that his very soul is being poured out. In this way, the man will always exist inside of them.

When their body is filled with warm spirit energy, they realise that they are not alone, their once empty heart becomes filled with warmth and ecstasy. It is said that men who have had their body and soul seised by them and then became their husband, they will not be released even after death, when only their soul remains. They will end up continuing to have sex with them as their husband for eternity.

Also, sometimes, living men are not their targets; instead they trap in their cages the souls of men who died alone like them and make husbands of them. They say that when the living wander into their residence, they will show off while they make love.

Furthermore, even after obtaining a husband, their deeply jealous personalities do not change. Every time they encounter a pair of lovers or a married couple other than themselves, they get jealous and express feelings of rivalry.

If a couple is intimately making love, they will get jealous of it and fawn on their husband, as if to indicate that they would like to do the same. If there is a wife who devotedly serves her husband and smiles happily as she is able to make her husband happy with her own hands, then they will be extremely jealous and envious. They will then devotedly serve their own husband to the point that it becomes obsessive. In this manner, their flames of jealousy rage without limit and they won't be able to settle down, unless they are the most indecent and most loving couple.

Kenkou's Notes:
今回の魔物娘は青白く燃える火の玉（？）「ウィル・オ・ウィスプ」です.

The monster girl this time is a bluish-white ball of burning fire (?), “will o' the wisp”.

拗らせて死んだ魂はゴーストではなくこっちになることがあるんだとか.

The souls of those who died of loneliness may become one of these instead of ghosts, or something.

炎を収めているカンテラ・・・もとい、特徴的な檻の様なもので男を虜にしてしまうそうです（物理）

It seems they imprison men (physically) in a lantern containing flames... or rather something like a distinctive cage.