The 40k version of Martin Luther (not that one). A super-charismatic preacher who arose during the Age of Apostasy and was responsible for leading the rebellion that saw the death of Goge Vandire, the reformation of the Ecclesiarchy to prevent such an individual from ever appearing again, and the creation of the Sisters of Battle.
Perhaps one of the most widely recognized Saints of the Imperial Cult. A significant minority of Imperials believe he was an avatar of the God-Emperor himself, to the point that a faction of the Inquisition that pursues a goal of finding a way to reincarnate the Emperor is known as the Thorians. Trazyn has apparently claimed his skull as a trophy for his collection, though there are at least 3 such skulls known to exist. Guess we'll have to wait for the Reign of Blood Black Library event to find out.