Hemalurgic Decay

Hemalurgic Decay emerges in The Hero of Ages as the invisible erosion that saps stolen Allomantic and Feruchemical abilities each time a spike changes hands. This decay is not a physical rusting but an intangible weakening that renders spikes progressively less potent, forcing Hemalurgists to seek fresher, more powerful donors. Across the series it transforms from an obscure technical detail into a strategic liability that shapes the final conflict, compelling characters to weigh the diminishing returns of spike reuse against the moral cost of fresh murders.