I guess I see a potential based on your starting statement. We don't know what the motivation of the Faceless men was. From the get-go they saw her as a person with a kill list. She wanted people dead. When offered to be trained, she turned it down, conflicted. In favor of looking for her family.

Well, we know how that went. And when she decided to go to House of B&W. They made her prove that she wanted to be there. Made her prove that she could strip everything away, to be exactly what she needed to be, in order to perform.

They push her in S6. Beat the confliction out of her. She has to be one-gear. Full hate. And be able to do it in the shadows. They needed her zero'd in. And in the 2nd to last moment, she chose Mercy. Which means = confliction. He was disappointed, bc she had "many gifts" — lots of people on her list. In short, the people B&W wanted dead.

But there was one last test. One he thought she might fail. But she didn't. She passed. She listened to Syrio, and all of it became a teaching. Resulted in her have zero conflict with herself. She's game on. Kill time. Forget going west young man.

He achieved in her what he always wanted of her.

She has a name, she knows where she's from,but she's also no one. Shadow-walker. Can be anyone with any face at anytime.

you are right, we don't know enough, but to look at it from the other end, no one is just the ability to strip of yourself. Maybe he was always scouting her...they had big plans for her. They trained her, and she's ready. I'm not sure she realized she's doing their bidding. But all I mean, is there may be a lesser known agenda.