Changes

During the [[Horus Heresy]], Tuchulcha was discovered by [[Lion El'Jonson]] in the [[Perditus System]] after [[Death Guard]] under [[Calas Typhon]], which also sought the artifact. The Lion prevented [[Calas Typhon]] of the [[Death Guard]] from acquiring the engine for his own twisted ends and was determined to use it to defeat the [[Night Lords]] and their [[Primarch]], [[Konrad Curze]].{{fn|1b}} Lion El'Jonson began to converse frequently converse with the Tuchulcha in the aftermath of the battle, confiding with it above all others.{{Fn|3}} During the attempts to breach the [[Ruinstorm]] and reach [[Terra]], Tuchulcha demonstrated the limits of its abilities. It honestly told the Lion honestly that it could not navigate the storm to Terra on its own, frustrating the Lion.{{Fn|4}}

Much later in the [[41st Millennium]], [[Cypher]] revealed that Tuchulcha was embedded within The Rock and that the [[Dark Angels]] ' dark history of [[betrayal|The Fallen]] could potentially be changed by finding the other two engines and changing history. He also warned that [[Astelan]] and [[Typhus]] both sought the engines as well. Eventually all 3 devices were gathered, and a warp rift was summoned over the ruins of [[Caliban]]. Convinced by [[Ezekiel]] to leave history be and trying to prevent nearby Fallen forces from accessing the rift first, [[Azrael]] destroyed the rift{{Fn|2}}.

The Tuchulcha remained aboard The Rock thereafter, in a vault carefully guarded by only a select few of the Chapter. [[Vashtorr the Arkifane]] sought the Tuchulcha along with its sister devices in order to create [[The Key]] in order to ultimately access an Old Ones device dubbed [[The Weapon]]. In the [[Arks of Omen Campaign]], Vashtorr first failed to steal {{PAGENAME}} when he boarded [[The Rock]] during the intervention of [[Be'lakor]]. However , in the [[Battle of Idolatros]], Vashtorr succeeded in contacting the {{PAGENAME}} and moving it to [[Wyrmwood]]. Together with its sister devices, the {{PAGENAME}} created the [[Dissonance Engine]] which bore a tunnel into the space between the Materium and [[Warp]] not unlike the [[Webway]]. With this new rift, Vashtorr seeks [[The Lock]] and with it The Weapon.{{Fn|5b}}