During your stay in Sagus Cliffs go to Fifth Eye Tavern (M10.3), where you can find Ghostly Woman. Interacting with her and allowing her to strangle you unlocks Ashen Imitation side quest. One of this quest's part is to find the so-called ashen women, the copies of Ghostly Woman. Below, you can find their locations.
COPY 1) The first copy is Seria and in order to meet her you must complete another side quest - The Sorrow's Prey. When you finish that quest, Seria stays in the Labyrinth. She can be found in the same place where you spoke with Ghostly Woman.
COPY 2) The second copy is Loss-of-Self and she can be found north of the tavern in Cliff's Edge district (M6.1). Speak with her and say that she reminds you of a woman from the tavern.
COPY 3) The third copy is the girl called Avina, who can be found standing with other orphans, south of the tavern in Cliff's Edge (M6.8). Speak with Avina and tell her that she is similar to a woman in the tavern. Ask her about the details and you can learn that she also is haunted by a ghost.
COPY 4) The last, fourth copy is Sigyn, the captain of levies. You can find her near the closed Council Tower in Government Square (M5.1). Like with previous women, speak about her familiar look.