13th Black Crusade - Echoes of the Past: Belisarius Cawl hadn't intended to remain on Eriad VI. Logic dictated he leave. Protocol insisted. Every moment he lingered, the greater the toll inflicted upon his forces by Gangrek's inheritors. And yet, the Archmagos could not bring himself to depart. The mystery called to him, stirred emotions long-atrophied by millennia of self-augmentation.He had to know the meaning of Veilwalker's cryptic advice. Was it tied to the reliquary concealed aboard the Iron Revenant? Could he take the chance that it wasn't? The Shadowseer had implied that the secrets of Eriad VI would be uncovered now, or not at all. Cawl didn't doubt that his and Veilwalker's interests were at best in temporary alignment, but even a fleeting alliance had the potential to alter the Imperium's course. He'd seen it happen so many times -- even if he could no longer recall the details, or even the names of those involved. Too many broken fragments of yesterday, scattered like a mosaic. For all of Cawl's attempts to preserve it, the past lacked the texture of today.Thus Cawl dug deeper, even as the defences of his compound wore away beneath the fury of Eriad VI's radstorms, and the bellicose deeds of the Greenskins. Each ruddy dawn brought fresh assaults on the perimeter, each night saw bastions abandoned as Skitarii fell back to secondary lines.Still Cawl dug, pushing the borers to their limits in his hunger for knowledge. As predicted, each new level excavated brought greater knowledge. The fragments grew larger, the warping less pronounced. One piece confirmed the Archmagos' growing suspicions: the artefacts of Eriad VI predated not only Humanity, but most other life in the galaxy. The techniques of forging, the absence of visible circuitry -- these all pointed to an origin in the darkest of times. Perhaps at the hands of the Old Ones themselves, or else the Necrontyr.Cawl's quest encompassed all thirty-seven solar hours of the Eriadan day. The deeper into the planet's crust he dug, the more urgent his search became.Occasionally, he caught Veilwalker watching him from the shadows.The Aeldari Shadowseer seemed visible only to him. She came and went as she pleased, passing through shielding-lines and vacuum bulkheads like a ghost. Cawl came to wonder if she was truly there at all, or conjured by memory augments suffering rad-degradation. Each time, Cawl's conclusion was the same. It no longer mattered. The madness of discovery was upon him. He had to know.By the fifth solar day, the Skitarii had fallen back to their inner perimeter. The Orks had suffered horrendous losses for their victory, but that only made them strive harder. The compound had become a challenge -- a guarantee of a worthy fight on a world otherwise bereft of life. All projections insisted that if the Greenskins launched another sustained assault, the compound would be overrun. Unfamiliar frustration crowding his secondary lobes, Cawl at last issued the order to withdraw.It was then, of course, that the breakthrough came. As the colossal tunnelling machines settled into their final excavation patterns, one breached the roof of a vast natural cavern. The weakened rock beneath its treads gave way, and the borer plunged into darkness. The machine's bleating warning signals were severed by the finality of its impact with the stalagmite-strewn cavern floor, but its last transmission contained images of a slab-sided structure of black stone. At once, Cawl issued a hold on the evacuation. Commanding the Skitarii to defend the landing zone until his return, he descended into the depths.Without warning, veilwaker was there, mask swirling with unreadable emotion. "Do you understand?"Cawl nodded, too horrified by the implications to object to her presence. "The pylons. The Immaterium...""The one holds the other to its rhythm." Veilwalker's mask was an angry red. "Without these stones, dancers become slaves to a refrain bereft of order. The galaxy dies, reborn in madness.""Can it be prevented?""Cadia is the end and the beginning."Cadia. Where the pact was first forged. Coincidence? Cawl no longer believed in such things. "This is too important for riddles. Answer me plainly!"But Veilwalker was gone, leaving the Magos with no answers, but perhaps a place to seek them.