The Witchlight is a fungus that grows on the edges of bogs, typically on rotting wood. Sometimes known as Wanderer's Friend, this moss almost always grows at the very edges of peat bogs and dangerous pools and glows with a sleight blue aura, saving many travellers a year from drowning. This is how the Witchlight has become the friend of travellers. Having a staff being overrun with witchlight is the sign of an experienced traveller in blighted swampy lands.
Midwives and wise women are aware of the value of the Witchlight as a curative, mixing it with mother's milk to cure a colicky baby. The form it into a paste with peat and moonlight to cure many poisons, especially snake bites. These wise women will often gather Witchlight only during a new moon, since it seems to grow most under the light of the moon, this lets it sustain itself and perform its mission. Similarity, it's considered bad luck to pull a fallen tree from the edge of a bog, since it's taking from the witchlight itself. Witches will also often leave small offerings of copper coins and wax for the witchlight itself in order to help it stay healthy, and its glow watching over the bog.
The secret is that the Witchlight is intelligent. All of the Witches of the Woods know. The Witchlight is the spirit of a bog, the combined spirit of all those that the bog has consumed, the mind that keeps the bog safe. It isn't evil, it has a fondness for all life, and wishes to make its home safe and welcoming. But it also cries out to become a greater being. The Witchlight really wishes it had a body, and it works to claim one.
When Witchlight is placed within a wound, it will take root and begin to grow. This often happens when a wounded traveller is running through the bogs away from something, and the Witchlight manages to get itself into a cut on their leg or hand. It wont be easily visible at first, since the moss will be a small amount, but after about a day the spores will grow into a small mass of light. Those who this happen to will often attempt to remove the Witchlight from their skin in panic, which is an Ob3 Blood letting test or an Ob5 Field Dressing test or else it will manage to re-grow by the next day. Those who don't manage to remove it, or simply leave it, notice they can see beyond the veil. When the pale blue light glows on their skin, they can see ghosts, spirits, and auras, they have gained the second sight trait. This extra attention in the spirit world means they might notice that, once they have a full patch (about a month's growth), they can touch spirits with their affected limb (treat their strikes as Spirit Weapon, and they can interact with spiritual things). Many a ghost hunter has kept a small amount of Witchlight around to grow in their skin and allow them to battle a hungry ghost or spectral echo when necessary.
However, this is not the end of the plans of the Witchlight, for it still needs the body. When the person with Witchlight growing in them dies by unnatural causes, they rise again after nine days, their body stitch together with a strange fungus, and their eyes glowing with a faint blue light. The fungal creature isn't violent or aggressive, they are in fact quite calm and helpful. They simply desire to live along the edge of bogs, help travellers, and attend to the needs of the local spirits. Of course, few who see their murdered friend (or worse enemy) rise from the dead will treat them that way.
Witchlight Zombies have the beliefs, "I will protect the innocent" and "Look to the Nameless Spirits to guide my actions". They have the instincts, "Never step into a pool" and "Make an offering every morning to the spirits". They have the physical stats of the person whose body they are using, they have Will B5 and Perception B4. They do not have skills, but they have Celestial Sight and the ability to divine the past and the future by speaking to the spirits. They cannot speak, except to the spirits, and therefore most will need to find an intermediary to speak to them. Witchlight zombies who manage to survive in bogs often become the protectors of a small area, preventing encroaching damage, keeping the local spirits happy, but also defending and feeding the local community in whatever small way they can.
A Burning Wheel Monster Every Week