Born on an orbital plate above Terra, the boy that would become Zardu Layak lived among criminal monks that worshiped a myriad of artifacts and faiths they discovered in the more ancient regions of their orbiting platform. One day Warriors in Grey arrived and mercilessly massacred the monks. Layak was the only survivor, and after being found weeping before the destruction of religious artifacts was subsequently inducted into the Word Bearers.
Following the legion's humiliation at the hands of the Emperor, Layak eagerly embraced the teaching of his Primarch Lorgar as well as those of Erebus and Kor Phaeron. However even these did not fill the void in him, and he soon began having visions of his Primarch speaking directly to him, telling him to not burn books but rather learn from and covet them and eventually discover the truth the Emperor had kept from his sons. Ashamed, he kept these visions from his comrades. Eventually he took a new name from the Book of Lorgar, was reborn as one of the Gal Vorbak, and became First Chaplain of the Chapter of the Ochre Gate, which after he corrupted its members became known as the Unspeaking. After his rebirth, Zardu Layak donned a daemonic helm chained directly to the flesh of his face and pledged to never let any but the Chaos Gods themselves see his face. Layak went on to participate in the Battle of Calth and replaced the roles of both Erebus and Argel Tal as Lorgar's closest confidant in the later stages of the Heresy.
Following the Battle of Beta-Garmon, Horus ordered a general muster of traitor forces to Ullanor, something Lorgar had at first glance agreed to cooperate with. In truth, Lorgar had come to view Horus as weak and planned to dispose of him and take his place as Warmaster of Chaos. Using Layak and the oracle of Cyrene Valantion Actaea as part of his plan, Lorgar traveled with them into the Webway in hopes of finding Fulgrim. After confronting Fulgrim in the Palace of Slaanesh, Zardu Layak obeyed Lorgar's order to bind him with the newly elevated Daemon Prince's True Name. Zardu Layak had been given the name in a ritual led by Lorgar, but the total amnesia it would eventually give the user meant that the Primarch had put the burden on Layak instead. Layak effectively had Fulgrim under his own will, but at a great cost. However Layak secretly had doubts about Lorgar, expressing resentment at his enslavement by the Dark Powers.[2a]
At Ullanor, Lorgar's coup was undone when the Warmaster revealed he already knew of the treachery. In the end, Layak released Fulgrim from his bindings instead of having him attack Horus as Lorgar had originally planned. A defeated Lorgar was banished from Horus' site, but Layak and the 5,000 warriors of the Unspeaking pledged themselves to the Warmaster for the coming Siege of Terra. Layak later conversed with Actaea, revealing that he had already forgotten all of who he was before recent events. He also revealed that he knew Actaea was the one who had informed Horus of Lorgar's treachery. Furthermore, he had investigated Actaea's past into the Cult of Cyrene Valantion and found that nobody by that name ever existed. Layak asked just who or what exactly Actaea is, but she refused to answer.[2a]