do fyreslayers actually have anything to do with the original slayer oaths from whfb or are they and their religion an entirely new thing that only resembles it aesthetically or draws from some of the themes?

i mean in lore continuity, the dwarfs from the world that was all or mostly died right? is there a direct lineage of slayer traditions that had been passed down through survivors or divine edict and then eventually evolved into the fyreslayer cult, or did grimnirs death inspire the fyreslayers cult spontaneously with no ties to the old slayer traditions, and they just happen to resemble them because thats grimnirs aesthetic?