The Coven of Isha is a secret pact between some members of the Ordo Xenos and the ancient Farseer Eldrad Ulthran of Craftworld Ulthwé. According to the Coven's librarium, the information provided by the Eldar through this pact has been linked to a number of disastrous events that engulfed the Imperium of Man, including the Sanapan Scouring, the Mortis Annihilation, the Third Coming of Orian and the First War for Armageddon. The Coven has rarely been invoked, for the Eldar rarely require the help of the Imperium, and the Imperium never looks toward xenos for help. The most recent time that the Coven was activated was when Deathwatch Space Marines from the Ordo Xenos had to help the Craftworld Ulthwé to counter the Dark Eldar's recent raids that took many Ulthwé prisoner to Hesperax, the homeworld of Lelith the Wych Queen. The prisoners were taken to be slain in Hesperax's gladiatrix games.
The great Eldar Farseer Eldrad Ulthran had created a special Wraithbone chamber hidden aboard the Inquisition's secret space station located in the Ramugan Sub-sector for the Ordo Xenos which could be used for communication between the Inquistion and the Seer Council of Ulthwé. The Inquisitor Lord Seishon was summoned there to hear the request of Ulthran that the Imperium aid the Eldar in securing Craftworld Ulthwe by recovering a lost Eldar relic. The Inquisition's Ramugan space station had stood for millennia, and dated back to the time of the Great Crusade when the Emperor Himself was still actively leading the Imperium. The station was home to delegations from the three main branches of the Inquisition: the Ordo Xenos, the Ordo Hereticus and the Ordo Maulleus.
The Seer Council of Ulthwe was convinced to accept aid from the "Mon-keigh", an action that some members of the Council, such as Ruhklo, saw as an insult, but the Emerald Seer Thae'azki and the Seer Eldressyn, who had been chosen to serve on the Council by Ulthran himself, insisted on accepting the humans' aid. At last the decision was made. A Deathwatch Kill-team departed from Ramugan on the Lance of Darkness frigate by order of the Ordo Xenos to recover the relic for the Eldar and uphold the Coven of Isha. The Kill-team included the excellent Astartes from some chapters, Emperor's Champion captain Octavius originally come from Imperial Fists, chaplain Luthar from Revilers Vigilant, librarian Ashok from Angels Sanguine, librarian Atreus of Blood Ravens, Kruidan of Mantis Warriors, the Iron Father Sulphus from Red Talons and Pelias, Sergeant of the Black Consuls. They soon join a conflict against a Dark Eldar's raid. Realising the Guardian of Ulthwe were such wimps, and the darkned soul of Ulthwe's citizen, they barely had a gut to stand a ground and will retreat when aid come, even from the "mon-keigh". Next, they followed the request to patrol the Khalandhriel’s Hall of Ulthwe from warlock Shariele, and confronted some Dark Eldar troops there. Abruptly, Ashok dissapered, it later to show up that he was ordered by Lord Inquisitor Seishon to find the Infinity Circuit of Ulthwe and set up a beacon there so that the Inquisition can keep track of Ulthwe should it depart, and he successed. However, he was captured, disabled and taken to Hesperax by the Ulthwe's seers as a "gift", a secret bargain between the Emerald Seer Thae'azki and Lelith.
After wrecking havoc on the raid, the Deathwatch Kill-team was summoned to the seer council and was allowed to patrol the space and find traces of Dark Eldar movements. The Lance of Darkness depart, bringing the whole team and two accompanied Eldar, warlock Shariele and Shining Spears's Exarch Dhrykna. They soon find a squadron of Dark Eldar Corsair-class Escort, and gave a chase. The Corsairs were no match for the Lance of Darkness, and only one of them escaped the assault, by order of Captain Octavius so that they can find the Dark Eldar's base. The survival Corsair fled home, it fly through a warp gate that was camouflage as a asteroid. Soon after pass through the warp gate, Octavius found Hesperax. He risk landing on the planet, wisely divided his team to two Thunderhawks and set to the planet's surface. The first Thunderhawk was under command of Kruidan, and the second was commanded by Octavius. They dipped in to the planet atmosphere. The Kruidan group landed first, and was ambushed by hundreds of Dark Eldars, Kruidan used his jet pack to repel the arriving enemy and bombing them from the sky. His squad fight fiercely, but was overwhelmed by waves after waves of the darklings, to the point that they were crushed and taken prisoner, Kruidan was shooted down and hurted, his Power Amour broke at his back. The Octavius group wasn't better, his Thunderhawk crushed down, and by the time they were able to stand up, they was surrounded. They were "gifted" to the darkling by the treacherous Emerald Seer Thae'zaki, a secret bargain between her and Lelith the Wych Queen, to lure and trap some "mon-keigh" warriors to serve in the Hesperax's gladiatrix. This was predicted by Eldrad Ulthran long ago, and he directed this for his bigger achives.
The whole kill-team and two accompanied Eldar warriors were taken to the bridge. Their captors hadn’t even bothered to remove their power armour. Instead, the dark eldar had simply shackled the ankles and wrists of the Marines, pulling them tight against the wall. There was not a chain or a lock in the Imperium that could restrain a Space Marine in full combat armour, but these shackles were made of a material that they had never seen before — they appeared to be made out of the darkness itself. Kruidan was badly hurted and the darkling mended him to some point so that he can stand and fight in the next round of the gladiatrix. Octavius was angered by the view of some remaining of human limbs and power armour remmants, evidences of operated and exploited body of his suffered brothers Space Marine that was there before. No Deathwatch was taken here, though. Later, the two Eldar warriors were cut down and taken to the Gladiatrix to fight for entertaiment of thousand blood-thirsty Dark Eldars. With bare hand, they fought valiantly against three mounted Wyches. Shariele was able to kill one of the Wych and died, his soulstone ruined in combat. The Shinning Spear'sexarch Dhrykna still fight on. The whole Deathwatch kill-team was dragged here to see the show, with some locks on their bodys and they had to moved with extreme difficulties. At there they reunited with librarian Ashok, who was put in a hard cage. Shortly later, their body's locks were removed so that they would fight next.
In a room, Lelith meet the Slaanesh's Daemon Prince( who appered to be a immaculate princess with breathtaking body). The Daemon princess seduced Lelith, the one who dared to toyed with Slaanesh's daemon, so that the Wych Queen would gather more souls to bring the princess( and her minions) into the materium realm. After a while, Lelith took her seat in the arena, with two other Eldarfarseers that was tasked with taking the temporarily disabled Ashok( though later Lelith informed them that they were sold goods, too). The old farseer Bhurolyn and the young Xhelkisor were shocked, and Bhurolyn slammed into the ground. But he immediately realised that Eldrad Ulthran would never betrayed him, and could it be himself was meant to be a last surprise for Lelith? The old farseer punched forward and sent a javelin of power crackling through the arena. It slammed into the massive, slowly opening doors and blew them apart, shattering them instantly and sending shards of metal and masonry flying around the amphitheatre like hail caught in a hurricane.The crowd went wild.
Dhrykna dashed over to aid the two farseers. The Deathwatch crushed the distracted darkling guards, each of them now wielded two darkling's swords. They fought back to back against waves after waves of gladiatrix's Wych. The crowd continued to go wild, shrieking and braying like wild animals, they had not seen such brutal yet exciting game lately. Suddenly a Talos Pain Engines enter the arena. Octavius was forced to deal with the new threat. The wych queen herself, who overcame by the voyeuristic thrill of combat, had vaulted down into the arena to join in. Both of Deathwatch librarian helped Dhrykna to deal with the Wych queen. Kruidan was already charging across the arena to assist his captain; Pelias and Luthar were giving chase to the fleeing wyches; and Sulphus was studying the mechanical monster that was attacking Octavius. Captain Octavius, with two ruined blades in his hands, was wrapped by the Pain Engines, he struggled to detach himself from the barbed talon that impaled him, but every movement simply drove the spines deeper into his flesh. When Kruidan arrived to help him, Octavius was nearly dead and ate by the monstrous Engine. As he vanished from view, Kruidan thought that he had heard the captain’s last defiant words, almost swamped in the cacophony of the arena: “Primarch — Progenitor, to your glory and the glory of Him of Earth!”. Kruidan went frenzied, climbing upon and hit it with his hardest blow. Sulphus the Iron Father also climbed up on top of the Engine, too. He set up a demolition charge inside it. The Engine spilled shells anywhere, and Sulphus did his last strike. The Engine exploded. Sulphus was able to get with him the yellow shoulder coat of the heroic captain. Dhrykna the Shining Spear fell to Lelith poisoned blade, but was able to wound Lelith somewhat badly.Lelith withdrew. Ashok helped to kill the suffered Dhrykna spirit stone instanly, and took her spiritstone and two other of the died seer with him so that their soul would be saved from the Dark Eldar
The remaining team of Deathwatch to dove out of the arena and through into the shadowy corridor, Sulphus used the explosive and shells taken from the wrecked Talos Pain Engine. Sulphus exploded the wall, blocking the chaser from catching them. They ran through the lobby that lead to a chamber. At here, Ashok confessed his knowledge about the plan. He showed out that the place was a nodal chamber, the place that hold the suffered souls of the Dark Eldars victims. It was also navigate point that could lead to other places. When Sulphus set up the explosives to demolish the place. The Wych finally surrounded them, and the Marines dig up a last stand. They fought valiantly to hold back the enemy. Then, Sulphus activated the explosives, blow up the whole chamber. The Marines fled to the gate, only had time to get back to the Thunderhawk and return to the Lance of Darkness. The freed souls of the long tortured released such gigantic power, and the destroyed portal was swept through with power from the Warp that incinerated the whole Hesperax planet, and the plan to summoned the daemon prince failed at the close call.
The kill-team escaped the collasped world, and in return to Ramugan space station, they honoured their honourable and heroic captain that sacrificed his life for the mission.
- Warrior Coven (Novel) by C.S. Goto