This achievement is currently not available in the Guild Wars 2 API and you are seeing the last known version. The achievement has either been removed from the game or needs to be rediscovered.
Part of The Facet of Prisms and Boundless Light Objectives Unlock all legendary Primordus weapon variants.
Tiers Objectives 1 4 8 12 16 Total Achievement Points 0 0 0 0 0 0
Rewards Data {"id": 6815,
"name": "The Facet of Fire and Destruction",
"description": "",
"requirement": "Unlock all legendary Primordus weapon variants.",
"locked_text": "",
"type": "ItemSet",
"flags":
["Pvp", "RepairOnLogin", "Permanent"
], "bits":
[{"type": "Skin",
"id": 10696
}, {"type": "Skin",
"id": 10491
}, {"type": "Skin",
"id": 10287
}, {"type": "Skin",
"id": 10366
}, {"type": "Skin",
"id": 10346
}, {"type": "Skin",
"id": 10345
}, {"type": "Skin",
"id": 10532
}, {"type": "Skin",
"id": 10645
}, {"type": "Skin",
"id": 10513
}, {"type": "Skin",
"id": 10388
}, {"type": "Skin",
"id": 10674
}, {"type": "Skin",
"id": 10579
}, {"type": "Skin",
"id": 10252
}, {"type": "Skin",
"id": 10660
}, {"type": "Skin",
"id": 10311
}, {"type": "Skin",
"id": 10288
} ], "tiers":
[{"count": 1,
"points": 0
}, {"count": 4,
"points": 0
}, {"count": 8,
"points": 0
}, {"count": 12,
"points": 0
}, {"count": 16,
"points": 0
} ], "rewards":
[{"type": "Title",
"id": 396
} ] }