Vethorel was a Tech-Priest and loyalist member of the Mechanicum during the Horus Heresy. Having few outwards bionics, Vethorel became the ambassador of the loyalist Fabricator-General Kane to the Council of Terra following the Schism of Mars. Charged with Kane with strengthening the ailing cause of the loyalist Mechanicum and bring the Collegia Titanica elements on Terra to heel, Vethorel attempted to legitimize Kane's standing by having the Mechanicum upgraded to Adeptus status, an act that would give them representation on the Council of Terra. She faced vicious resistance both from fellow Tech-Priests and Adeptus Terra members, including an assassination attempt by several Magos. Nonetheless in the end, thanks to the direct aid of Kane and an act of intimidation by the Legio Ignatum, Vethorel was successful in having the Mechanicum's status upgraded, creating the Adeptus Mechanicus.