Purge of the Black Medusa

The Purge of the Black Medusa was a castigation campaign launched by the zealous Castigators Chapter against a heretek conclave of Renegade Tech-Priests known as the Black Medusa that had repeatedly violated the Martian Accords and delved into forbidden technology and study of things better left unsaid.

History
Stationed at a remote Adeptus Mechanicus research facility, a group of Tech-Priests had banded into a heretical techno-cult known as the Black Medusa. In their testing chambers they began to explore long-forbidden sciences that was outside the purview of the Cult Mechanicus. Their heretical research resulted in a disastrous 'resonance cascade' that tore a rift in reality, devastating the facility and enabling daemons to manifest in the material realm. The Castigators fought alongside the mysterious silver-armoured Grey Knights amongst the ruins of the research facility an attempt to eradicate the daemons and seal the rift. The surviving techno-cultists surrendered and were executed for their heresy.