Mortimer’s Grimoire of Soul Magic: A Qualitative Study on Retaining and Keeping Souls by Karl Mortimer

Mortimer’s Grimoire of Soul Magic: A Qualitative Study on Retaining and Keeping Souls was a book hidden in Albrecht's basement, previously belonging to Kordt Gillenheim. The book contains a number of necromantic rituals, one of which was used to bring Gillenheim's spirit back to haunt and kill the townsfolk of Mistvale. It was written by Karl Mortimer, a former Excellent of the Arcanum.

Excerpts
[...] Once the body dies, the soul’s teather is broken, thus allowing it to continue on into the afterlife. In the first experiment, using a minor phylactery, the ritual successfully interrupted this journey by creating a new, artificial bond with the squirrel’s soul. The phylactery successfully retained it, preventing it from making its journey onwards. The second part of the experiment allowed us to capture another specimen’s soul within the same phylactery through a very different method.

[...] In the last experiment, the souls of the rats were initially trapped inside a simple rock through previously disclosed means, to later be reduced into a fine powder. By burning aforementioned powder, a sudden and violent reaction was achieved, creating a blast of pure arcane force that would be impossible without the use of the critter’s soul. In the second attempt, the reaction was recreated in a small enclosed box of brass with only a single opening. This time, the force could be focused through the hole. However, the box was severely singed in the process and had to be replaced. For the third attempt, the box was lined with a fine azure crystal in order to focus the blast further. In summary, breaking a necromantic bond with a Zenith rune inscribed on a fragile material unleashes a wave of arcane force with high purity, that in turn can be focused with a small crystal and brass container.

[...] In order to successfully perform a soul binding, it is essential that the caster is aware of the three mandatory components: the vessel, the conduit, and the anchor, each of which must be inscribed with the chosen rune. First of all, the ritual requires a way of housing the soul itself which is referred to as the Vessel. This component acts as a harbourage for the soul while it is in a resting stage. Moreover, the Vessel functions as the soulbound creature’s physical body while it is active. Secondly, the power of the bond passes through the Conduit, which must be attached to the spectral body of the soul. A typical Conduit can take the form of a necklace, bracelet, ring, or circlet. Lastly, the Anchor is what the tether is attached to, and much like the anchor of a ship, holds the soul in its place. The Anchor often proves to be the most complex part of the otherwise simple necromantic soul binding, as it requires a drainable source of life energy. The most common method is done by keeping trapped souls of critters in a small phylactery that the conduit can continuously drain. A less common method can be performed by directly draining the force from a living being. Contrary to popular belief, this method is less harmful than typically thought when applied to an average sized humanoid being, as its lifeforce is plentiful enough for both itself and the bond.