How to find the Black Knife Armor in Elden Ring

gamepur.com:

Central to the lore of Elden Ring are the Black Knife Assassins, female warriors who stole a piece of the Rune of Death and slew Godwyn the Golden, setting off the war of the Shattering before the game takes place. You can don the armor of these legendary women of Numen, but finding their armor will take some time.

You’ll find the Black Knife armor in Ordina, Liturgical Town, underneath the bridge leading to Miquella’s Haligtree.

You don’t need to complete the town’s evergaol puzzle to acquire the armor. Head to the stairway at the northernmost edge of the town and drop down on the snow to either side. There will be a corpse underneath one of the arches with a shiny item: the Black Knife armor.

Getting to Ordina is a trial. To access the Grand Lift of Rold that will lead to the Consecrated Snowfield, you need to first defeat Morgott, the Omen King in Leyndell, the Royal Capital. Then, you’ll need to collect the right and left halves of the Secret Haligtree Medallion. Return next to the Grand Lift of Rold and select “Hoist Secret Medallion.” You’ll traverse the Path to the Haligtree mini-dungeon and come out into the Consecrated Snowfield. Go directly north, and you’ll eventually reach Ordina, Liturgical Town, home of the Black Knife Armor set.