There appears to be a naming inconsistency between two of Bloodborne's most significant weapons—one that becomes obvious when examining their thematic purposes and wielders.
Gehrman's "Burial Blade" is the weapon of mercy:
Eileen's "Blade of Mercy" performs burial rites:
Both weapons are forged from siderite, connecting them thematically. The swap in naming appears to be either a development oversight or a deliberate inversion whose meaning has been lost.
The common fan interpretation identifies Eileen as a "plague doctor." This reading ignores significant visual evidence and misses a more coherent thematic interpretation: Eileen is designed as a scarecrow.
The wordplay: SCARE-CROW. She scares hunters (by hunting them), she IS a crow (her mask, her aesthetic), and she functions as a scarecrow—something meant to ward off threats, but in her case, she IS the threat to hunters who've lost themselves to the beast.
Visual evidence supporting the scarecrow interpretation:
She is also missing the iconic cane, which could easily have been a Threaded Cane. Instead, she wields dagger-like blades.
The scarecrow reading provides thematic coherence: Eileen wards off the corruption of hunters by culling those who fall, functioning as both guardian and executioner—a living scarecrow keeping watch over a field of potential beasts.