Sampo comes from legendary times, supposedly forged by the smith Ilmarinen in exchange for his wife’s hand in marriage. It is said to be one of the Five Keys which, when combined, can restore Kela the Guardian to her corporeal form.
Sampo was last possessed by the demigod/sorcerer, Louhi, before her ship was sunk 100 kilometers northeast of Kotime by the demigod/sea demon, Iku-Turso. Few scholars agree on what Sampo looks like or what its purpose was, but the most common explanation is that it was a huge, magical millstone. Other legends say that it was a menhir or obelisk that served as a world tree or the channeling point of a ley line nexus.
The Sampo - along with Iku-Turso, Louhi's ship, and a host of undersea allies of the demonic giant - was brought to a central plain in Kotime by a massive teleportation ritual. In a brief, catastrophic battle, the forces of elvendom destroyed Iku-Turso and its allies and recovered the Sampo. It has been brought to the Arcanum in Jumala for safe keeping and study.
Now that they have it in hand, the Sampo is a huge disc of extraplanar stone with a broad hole in the middle which can be set over an axis. The disc of the Sampo is split into a top and bottom portion, which can, when energized, rotate opposite one another. Providing magical energy to the Sampo, such as on a ley line nexus point, allows the Sampo to transmute raw materials into extremely valuable magical reagents such as orichalcum, phasic silver, or mana.