Sebastian Thor
The 40k version of Martin Luther (not that one) and John the Baptist. 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. Also his bones and head and such are valuable relics; the Sisters of Battle use his bones as centers of worship. A joke among the Inquisition is that if you were to gather all these bones, you'd discover Thor was actually a three-headed, five-armed freak of nature. His head in particular commonly finds its way into the hands of whatever famous plunderer the GW writers want to push is super awesome this year -- most recently Trazyn is the one claiming to have it in his collection. Guess we'll have to wait for the Reign of Blood Black Library event to find out.
