The act of one going to a crowded side of the city and causing an explosion with destruction is not foreign knowledge to the high echelon, nor is it to many of the ordinary citizens.
The tradition existed before the founding of the Abranyth empire, and its origin can be traced back to the ones who have proclaimed themselves enemies of all Gods.
The nonbelievers.
When it comes to religious practices, there are three major factions involved. The righteous believers, the forbidden believers, and the nonbelievers.
The righteous believers are affiliated with the Chapel of the Nine Gods. They are the choice of the people, the widely accepted and recognized option across the world.
For the forbidden believers, they are a group serving the Gods that are prohibited by the righteous believers, deliberately written off of history or portrayed by history in a way that they come off as antagonistic to the Gods of the righteous believers.