The day after the last battle, the Savior disappeared. Three days later, Severus Snape woke up from a coma in the Shrieking Shack and left the wizarding world, disappearing into the Muggle world without anyone noticing.
The wizarding world is still moving forward without a savior. People gradually forgot about the war and its effects.
Just like history will be forgotten one day. A hero is nothing more than that.
Three years later, almost when everyone had given up looking for their savior, a man named Sanes Peruves came to the University of Venice to apply for a position as professor of pharmacognosy, but discovered something unusual...