Van Horstmann's Speculum

Though the Empire's soldiers stand bravely against the dangerous monsters and dark champions that assail them each day, they are no match for these foes on their own. Prior to being corrupted by the Ruinous Powers and his uncovering as a Chaos worshipper, the Wizard Egrimm van Horstmann managed to craft a solution to this problem. The result was a small magical mirror with the ability to switch the fighting qualities of the wearer with that of their enemy. Fearing the possibility of being corrupted by van Horstmann's influence, the Light College has added a series of strong protective wards to the device to limit its power.^[1a]

Source

• 1 Warhammer Armies: The Empire (8th Edition)
  • 1a: pg. 63