Most unusual for a blood charm, thread spiders do not melt into their wearer’s body. Rather, it is their wearer’s blood, which melts into them.
When brought into contact with a magical treasure or thread item, the spider attaches to it by its tiny legs. This increases the Maximum Threads of the item to 8. From now on, the spider bites anyone weaving a thread to its host item, drawing blood with its miniature fangs. This deals Blood Magic Damage equal to the rank of the woven thread. If the same adept later weaves a new thread of higher rank to the item, the Blood Magic Damage increases to the new rank.
If the thread spider is detached from its host item, the Maximum Threads of the item immediately return to normal. Any excess threads vanish, starting with the oldest thread.
Legend has it, that these unusual blood charms first originated from a kaer in the depths of the Liaj jungle.
Here, a race of living silver spiders is said to have been used by the kaer’s defenders to weave their stunningly complex astral webs over and between the kaer’s limited supply of thread items and other magical treasures, connecting all of them.
In case of a breach of the outer barriers, the defenders would have been able to hand over their weapons from one to the next and pick up the treasures wielded by the fallen, without ever fearing to diminish their usefulness.
Whether any of these living thread spiders remain – in the mighty jungle or deep within the legendary kaer –, nobody knows for sure. And so, it also remains a mystery what other strange abilities these creatures might display.
What is known for sure is just that some time ago, initially in the cities of Jerris and Kratas, the first of the silver blood charms were sighted.
A thread spider has a Depatterning Rating equal to half the number of adepts (round fractions up), who currently use the spider. If, for example, four members of a group use the thread spider to weave threads to an item, the charm’s Depatterning Rating is 2. When the fifth member of the group later on decides to also weave a thread to the same item, the Depatterning Rating of the charm immediately increases to 3!
Thread spider blood charms are very rare in Barsaive and elsewhere. When they can be had at all, their price is never less than 2000 silver pieces.