My priest friend came up empty offhand, but suggested looking at saints in the Lutheran church, as they’re big in Germany. Also, he said to focus on martyrs. The orientation of the axe suggests that this guy could be a martyr. He said they were frequently depicted with the item that they were martyred with, and the axe is pointed towards him, rather than away which would suggest using rather than receiving the edge.
Good luck. I googled and checked images for over an hour and came away empty.