|This page contains spoilers for:||The Mistress of Threads (Short Story)|
They used their business dealings to spread Genestealers across the sector and also used them to corrupt other merchant groups, so the Cartel could easily take control of them. In the last years of M41, the Cartel had their sights on gaining control of the merchant company of House Morio and had begun to infiltrate it, when the Great Rift was created. This was a great opportunity for the Cartel, as the giant Warpstorm wreaked havoc on House Morio's trade deals and caused the House to fall into massive debt. When House Morio could not pay its debt back, its creditors hired Bounty Hunters to capture the House's owner Osric Morio and his wife Cressida Syr Morio, who was the House's Executor. By that time, the Cytos Cartel had infiltrated House Morio and had already infected Osric. Under their influence, Osric suggested to his wife, that House Morio seek the Cytos Cartel's aide in dealing with their creditors and Cressida readily agreed.
This began the House's downfall, as while the Cartel paid off House Morio's debts, they began to quickly infect the House's members and also started using Morio's reputation and its personal seal to further spread the Genestealer Curse. However Cressida would later discover a Genestealer frozen in one of House Morio's package crates and though she did not know what it was, its appearance greatly frightened her. This led Cressida to look into the Cartel's usage of House Morio's holdings and resources and what she discovered made her uneasy. Now feeling that both she and her husband's lives were in danger, Cressida contacted her cousin Viola von Castellan, Seneschal of the von Castellan Rogue Trader Dynasty, and requested help. Cressida knew Viola and her brother Duke, were serving the Inquisition and asked that they use its resources to look into the Cartel and then do what was necessary. Viola agreed to help and after using her Dynasty's resources, and that of her patron Inquisitor Covenant, she discovered that the Cytos Cartel was a Genestealer Cult. With the truth revealed, the von Castellan Dynasty and Inquisition immediately destroyed the Cytos Cartel, in what became known as the Cytos Purge.