Scouring of Mendron

The Scouring of Mendron was an Imperial campaign of reciprocity carried out by the feral and bellicose Seraphim of the Abyss Space Marine Chapter against the infamous commander of the Fallen Angel, Mendron Tihr, in revenge for the destruction of their home world of Boletaria

History
Mendron Tihr, a general of the Fallen Angels' assault on the world of Boletaria, had taken his forces as far from the cataclysmic aftermath of aforementioned battle as his ships could allow and thus ventured beyond the galaxy's rim to unknown space. Mendron thought himself safe and ordered his small fleet to find a safe harbor and repair their vessels, and eventually created a sanctuary after several years. However, the Seraphim of the Abyss were in hot pursuit, hearts filled with a grieving rage. Under the new guidance of Grand Master Hademar Kadmael, the Seraphim discovered Mendron's army had created a new home in the form of the world called Griffaine. With revenge in mind, the sons of the Lion dispatched small teams to sabotage the Fallen's critical facilities, such as fueling stations and void shield generators, so whence the Seraphim's fleet arrived in orbit around Griffaine with guns ablaze.

The Fallen then tried to muster a defense against the raging Seraphim, but found that many of their ships were crippled when their fueling lines were detonated. They would not have long to think of another plan, as the sable and azure Seraphim descended to Griffaine's surface, into the heart of the conclave of traitors. The Grand Master led the 1st Company into the various hab-blocks of the planet whilst their brethren seized and abducted Fallen around them, dragging them back to their Thunderhawks after sapping the power from their armor. Hademar Kadmael later found Mendron Tihr in a towering spire at the center of the "sanctuary" and stormed the fortress, though it was into the jaws of the beast.

Devious and desperate traps and ambushes assailed the Deathwing and Grand Master at every turn and level, claiming the lives of many Deathwing Knights during the ascent. Though their assault was blunted, the Seraphim's hatred was only fed before they found Mendron at the peak of the spire, surrounded by an air of the Ruinous Powers. In the face of retribution, the Fallen Angel had accepted the whispers of Chaos and unbridled power surged through the traitor in ancient Terminator Armor. His attacks were devastating and blinding, slaughtering Seraphim left and right. Mendron's Power Axe even smote Hademar Kadmael's helmet and permanently disfigured his face, but the Grand Master sliced through Fallen's armored back, and took up a device used to interrogate captive Fallen, a rod capable of delivering a paralyzing shock, and plunged the device into Mendron's back and activated it. Screaming in sudden agony, Mendron Tihr's body spasmed uncontrollably and fell, twitching wildly. Prying the defeated heretic from his armor, the Deathwing carried their wounded Grand Master and quarry back to the Battle-Barge Shadow of Loyalty before the Chapter fleet eviscerated Griffaine as the traitors had destroyed Boletaria.