It goes on for several nights. As he spars with her—being careful to teach as few real lessons as possible—he tries to understand who she is and what drove her to serially killing members of the court.

Of course, he isn't really courteous about it. "Why do you condemn men whom you have never met, about whom you know nothing?", he asks once.

"I do not need to know you all in person to know your character," she replies sternly, blocking one of his blows. "A man's actions are what define him."

He raises an eyebrow. "So you kill people based on their reputations," he spats. "Based on what you heard about them."

"I've already told you the reason behind every single kill of mine so far," she sparts back. "I don't recall you rebuffing any of those. Do you deny that your father killed hundreds of men, women and children for a crime undeserving of the punishment, and which most of them did not commit at all?"

"Kill a lord, and his children will avenge his death," he replies, reciting what Tywin Lannister himself told him once. "Kill all the family, and no one will avenge them." He blocks her blow. "It's the same principle behind the sack."

Not that he agrees with his father, but the ghost doesn't need to know that.

"His reasons were as dishonorable as his actions, then," she replies. "Are you going to defend another of your dead friends?"

"They weren't my friends," he retorts. "And who is next? You told me about myself, my sister, Joffrey and King Robert. Are you going to get rid of the whole court?"

She charges at him, but he blocks her rather easily. She sighs and lowers her sword, signaling a reprieve. He briefly thinks of taking advantage of her momentary relaxation to stab her, but he doesn't think he will succeed, so he stops himself from doing such a stupid thing. After he lowers his sword, she speaks up. "Jon Arryn married a woman who didn't want him for the sake of an already forged alliance."

"People marry against their will all the time," he replies, although he can't help but agree with her statement.

She ignores his rebuttal. "Stannis Baratheon invaded Dragonstone to kill a pregnant woman and her son who did nothing against his brother, or the realm."

"Viserys Targaryen would contest Robert's claim," he argues, but it sounds hollow to his ears. Rhaella's screams still plague his nightmares.

"Most of the Kingsguard break their vows in the same way you do with your sister," she goes on. "Although they take whores and servants instead. They often force themselves on them."

He grimaces in disgust. "I won't defend them," he says. "At least Cersei lays willingly with me."

"I know," she replies, almost soft. Then she goes stern again as she adds, "Ser Barristan Selmy served opposing kings."

"Kingsguard doesn't care about who sits on the throne," he replies instantly. As much as he and Ser Barristan don't get along, it doesn't mean he wants him dead, especially for doing his duty. "Or should not. Ser Barristan never swayed from his vows, as far as I know."

"No knight of the Kingsguard should outlive his king when that king dies by violence," she replies.

He remembers those words. "Cregan Stark," he hums. "You know your history, girl. Are you of noble birth?"

She visibly recoils at that. "We're done for tonight. Come back tomorrow."

"I'm on guard duty tomorrow night," he says, reminding her of what he already told her when he arrived.

"And the other night?"

"I'm supposed to be free." He is tempted to say he isn't, but, as she already proved, she can easily travel through the secret passages to check the information. He suspects she will do it tomorrow.

On his way back to his room, he ponders who the ghost might be. Her accent is strange, as if she wasn't born in King's Landing, and her manner of speaking does imply a noble education, now that he thinks about it. She must be from a noble house out of the crownlands.

He takes advantage of his Ghost-free day and night to ask the Grand Maester for a book about the noble houses of Westeros. The man frowns, certainly wondering why a Kingsguard would ask for such a thing, but lends it to him anyway.

Going through the damn book is a nearly impossible task. It's so boring, and he doesn't seem to be able to find any missing young lady.

At night, he goes to guard Robert instead of Cersei. Normally, he'd complain, but now, the more he stays away from his twin, the safer for them. The king decides he is going to die of boredom before any 'ghost' kills him, so he commands Jaime and Ser Meryn to follow him to a tavern.

The hours spent there are, as expected, dull. Men sneer at the Kingslayer, and women bat their eyelashes at Ser Jaime Lannister. He keeps a neutral grin on his face all times as Robert grabs many serving girls and brings them to his lap with one hand while grabbing a random woman'ass with the other. None will ever be a true Kingsguard who has not learned to wear a mask of gaiety over his sorrows and one of sadness, boredom, or indifference over his inward joy; it's a lesson learned from his time serving Aerys.

Would the Ghost ever care to ask why I killed him, he thinks for a moment, or will she murder me merely on the assumption I did it for my House? If she is to end my life, she should at least know why and judge accordingly. He decides to urge her to ask about his motivations… after he finds out which House she is from.

The following day is for investigations, so he chooses to sit down and take a good look at the book. As the energy to look for the killer dies out, few bother to check what exactly he's doing about the investigations. He knows Swann is not doing a damn thing, for example.

There are women listed as missing in a few houses from the Vale, most sharing an Arryn ancestry if he understood correctly. A few small houses from the North and the Reach have young girls reported as missing, although, for most cases, the ages don't fit.

He sighs in frustration as he closes the book and prepares for his nightly duties. He has an actual clue of who the ghost may be, but it's next to useless!

He goes through his usual way and finds her at their typical spot. "My lady," he greets her with a mocking bow.

"I'm no lady," she replies with a snarl.

"Oh, but you are," he all but purrs, drawing his sword. "You may fight like a man and live like the poorest of the smallfolk, but your speech doesn't lie, and neither does your understanding of court. You had a noble education." He delivers the first blow, only for her to block it. She's getting a little better at this; he can't let her improve much further. "Your accent is tricky though. I can't tell where you're from based on it."

"Years of living in King's Landing can have that effect," she replies in a neutral voice. "I could say the same about you. Your father had a much heavier western accent."

That… is not what he expected to hear tonight.

"Anyway," he says, clearing his throat as he raises his sword again, "why don't you tell me where you're from? Perhaps I could help you go back home, and you won't have to bear witness to this sinful court."

She doesn't raise her sword. It'd be the perfect moment to strike, but the thought barely crosses his mind when he sees her deflate. "I can't go back," she says quietly. "Never again."

He frowns. "What happened?"

Silence.

"My lady—"

"I'm no lady!"

"Why?"

"I did not earn it!"

He scoffs. "Nonsense. You don't earn a ladyship, you are born with it."

Silence falls, until she eventually speaks up again. "My septa always said I was a failure at being a lady," she says quietly. "Too ugly to look the part. Couldn't sew, couldn't courtsey, couldn't sing, couldn't dance… Nothing a lady is supposed to do."

He faintly remembers Robert's stories about Lyanna Stark. "Not all ladies do these things," he finds himself saying. Why is he trying to comfort a girl who wants to kill him? Why this sudden spur of chivalry?

"Well, that's not what I was told. And when Father took me here, her words all turned out to be true." She sniffs. Tears, he thinks dumbly. That's a good thing! A ghost who cries is less dangerous. "Squires mocked me, ladies turned their noses up at me, knights ignored me when giving flowers to little girls." He tries to remember a time when he ever did such a thing, but comes up with nothing. "I cried on my brother's shoulder, and he took me to explore the castle.

"I was happy for once… the walls did not judge me, and my brother loved me as I was. But—", another sniff, "—I don't know what happened. I tried to investigate, but never found out, even after all these years. But my brother, he—"

She's openly sobbing now. A better man would have comforted her, and a more scrupulous one would have killed her right away. Jaime is neither of these things, though, so he just stares at her, trying to process what she just said—

Oh, fuck. "Brienne Tarth?"

She raises her head at him abruptly. "How—"

"Nine years ago," he begins, "Lord Selwyn Tarth came to King's Landing with his two children, Galladon and Brienne. The two siblings had drifted away from the adults one day. Hours later, we heard the sound of walls crumbling. We only found Galladon's body, but Brienne was assumed dead as well." He takes a deep breath. "Your story fits."

"Then you know why I can't go back home," she says. "I know my father remarried and has new heirs now. I cannot go back to Tarth and steal inheritance to Evenfall."

"You wouldn't be stealing," he replies. "It is yours by right."

"By right, it should be Galladon's, but he's dead, and so am I."

"Why did you not go back to the Keep? Why let your father think you were gone?" He faintly remembers Lord Selwyn's somber face as he left the capital with his son's body. He was devastated by his children's deaths, more than Tywin would ever be had it been him, Cersei or Tyrion. Why did she not show up?

"I was lost for gods know how long," she replies, lowering her voice for unknown reasons. Perhaps those are hard memories to recall. "I got hit on the head, so I wasn't thinking clearly at first. For days, I walked through the cannals, fending off dirt. When I got out... With my injuries, people recoiled at me more often than not, so I had no help. A woman helped me once when I fainted, but today I can't even make out her face anymore." She shakes her head. "By the time I fully recalled I was in King's Landing, my father was already gone. The guards did not believe me when I gave my name; said no noble lady would bear my scars, and that Brienne Tarth died a fortnight prior. Then I tried to fend for myself, worm my way into a ship home. Nobody helped me. Eventually, I found a place where nobody would bother me."

"Here," he says.

She nods. "No one knows about this secret entrance, or these tunnels. It was better than sleeping out in the open, not knowing whether it'd be my last night or not. I only left to get food, and soon I learned I had to fight my way to eat and drink."

That's why she's already an okay fighter. The streets are an excellent place to learn, indeed. She goes on. "I carved this mask so I would draw less attention when leaving to get food and water. I'm so hideous that people would scream on sight, which gave me a lot of trouble. Life's been easier since I put this mask on."

Silence falls again, but he is the one to break it this time. "This doesn't explain the killings."

"Is the reasoning I gave you not enough?"

"If it was, I wouldn't be asking. Your knightly quest seems awfully personal."

She huffs. "I told you how I was treated. I… My first kill was a squire. I was seven-and-ten, and he tried to force himself inside me. I had no intention to kill him, but it was the only way, and… I thought, perhaps if I got rid of all evil men in the world, I could walk out in the sun again."

She sounds really, really fragile. "We should end our lessons earlier tonight," he suggests. She nods, and he leaves. Only later he realizes he should have killed her then and there.