I think that either had the supposed [Hero] become corrupt, and the supposed [Blacksmith] had to kill them in order to save either people or even the world, or that whole story is just a conspiracy made up by the Church/Temple in the past, someone that was jealous of the powers of the [Blacksmiths]
dayum
there's also the possibility that the [blacksmith] due to being hated for having said power wanted to show just how much stronger than the [hero]
The church needs really to fix their mistake. And soon.
It's all because of their lies and reactions towards the "so-called hero's death and defeat" to what should have been a "lowly" Blacksmith (compared to their special "heroes and heroines") that the Blacksmiths in their world were constantly being mistreated and racial judged by others as being either the weakest occupation or servants of the evil G OD. Just because their powers can rival the heroes'.
There could have been a good reason why that particular Blacksmith had to kill the hero like, for instance, the hero being corrupted by evil and they needed to be stopped. Or they were abusing their power, slowly turning a future tyrant or evil... becoming a danger to the people around them.
But the Church/Temple chose to spin it in different way, instead of telling people the truth. Choosing to demonize the other party, just to keep their prestige and political power.
It's simply disgusting and disappointing, when they are supposed to be people whom others can look up to. They are a bunch of jealous and corrupt people.