Serasian Control Stone

Serasian Control Stones are made of polished onyx and allow the wielder to control undead with their thoughts. In the Seras Empire undead are used for manual labor, and these stones are used to control zombies, skeletons, and other low-level undead to do work considered too dangerous or too boring for their mortal masters.
More powerful versions of these control stones are used by the Serasian military to control hordes of undead soldiers, known as "The Immortals." These stones were used to great effect during the Great Serasian Crusade. Although the Serasians were ultimately defeated by the Hadrianic Empire, the image of undead hordes ravaging the battlefield still haunt the nightmares of an entire generation of Hadrianic soldiers.
In Seras stones are usually worn around the neck with a gold chain. The high born and high-ranking Serasian military will often decorate these chains with jewels and ostentatious designs to signal their wealth and power. Contraband stones found outside of Seras are often much plainer in nature, as anyone caught with a Serasian control stone in the Hadrianic Empire is subject to arrest and execution.