Lannister Bastard

What if Tyrion Lannister wasn't the last child of Tywin Lannister? What if there was another? A child born out of pure lust years later? Saoirse Lannister, daughter of Tywin Lannister and a nameless mother, a maiden beyond the wall, fighter of women, killer of men, and a bastard. Jon Snow x OC (Season 5 and onwards)