(no real pairing)
As the youngest Lannister, you were doted on. You were your father's favorite child and he didn't make it a secret. You appreciated that your father could show some sentiment, but you felt guilty all the same. While he doted on you, he was tough on Jaime. He also underestimated Cersei and clearly loathed Tyrion. Tywin was always comparing your siblings to you and to each other while they constantly complained about your father's treatment of them. You hated it as you loved them all, but you felt that you had to choose between your father and your siblings. You were torn.
As you grew up, you felt like an outsider in your own family. You learned strategy and hunting alongside your brothers as well as the skills all higherborn ladies were expected to know alongside Cersei. And you were close to your siblings, but your father's clear favor made you feel like you were betraying them somehow. And if you sided with your siblings, you felt like you were hurting your father.
It got to the point where you decided that your family would be stronger without you. So, at the ripe age of 18 name days, you fled from Casterly Rock into the forest, determined to live off the land, hunting the way you'd been taught. You took none of your fineries with you. Only a little bit of gold to get you started and to commission some hunting gear better suited for a young lady. You had no idea the turmoil your little idea had thrown Casterly Rock into.
The next morning, the entire castle was abuzz with activity. When you had not appeared to break your fast, Tywin had sent a servant to check on you. You weren't in your chambers. Nor were you to be found in any of your usual haunts. Tywin was livid. How had the guards managed to let someone sneak passed them to get you out of the castle?! And furthermore, who had taken you in the first place?!
"Father, perhaps the kidnapper left a demand for ransom in Y/N's chambers? Did the servant look?" Tyrion asked. Without waiting for a reply, he climbed down from his chair and made his way to your room as quickly as possible. Cersei and Jaime followed at his heels. Once inside, Tyrion looked in the first logical place for any type of parchment that may have been left behind.
There, on your vanity was a note. But not from a kidnapper. "She wasn't taken. We need to get to Father." The three hurried back to Tywin, the elder two begging Tyrion to clue them in. "Y/N wasn't kidnapped," Tyrion said as soon as Tywin was within his sights. He gave him the note and Tywin read it out loud.
"She just...ran off? So she wouldn't have to choose between us? Did anyone know that we made her feel that way?" Jaime asked in disbelief. Tywin pursed his lips. "So it seems. I certainly didn't. Granted, a daughter does not share much in the way of feelings with her father." Cersei shifted a little bit but nodded. "We need find her. Don't we?" Tywin agreed and Jaime offered to stay behind. "She listens more to you three. And someone should stay here. To make certain things run smoothly."
"I agree. Perhaps then you will get the thought of knighthood out of your mind when your sister marries the king in three moons." Jaime grimaced, but gave a small nod. With that, your father, sister, and other brother left Casterly Rock to find you. They only hoped that nothing sinister had befallen you in the few hours that you had been gone.
*time skip brought to you by Robert's breastplate stretcher*
One month. That's how long you managed to survive out in the wild before you were actually seriously hurt. You hunted, sold the meat and furs to people in a nearby village, and were able to purchase a small but well-made hut for yourself, all in a month's time. To say you were proud of yourself would have been an understatement. You proved that you could be self-sufficient. That you didn't need the family name to succeed. But then, the injury happened.
You had been out hunting and gathering wood for your hearth when you got distracted. That one distraction ended with you being attacked by a doe protecting her young. You weren't fast enough with your arrow to take her down before she could begin trampling you. The only reason you made it out without worse damage was because someone else came along and scared the poor creature. You snapped your head in the direction of the intruders. "Father," was all you managed to say before you lost consciousness.
When you woke up, you found yourself in your own bed. How your family knew it was your hut, you didn't know nor did you think to ask. "Father, she's awake." You glanced over to see Tyrion next to your bed. He gave you a smile and patted your hand. The sound of footsteps caused you to look away from Tyrion to see Cersei and your father.
"Foolish child," was the first thing your father said, causing you to frown. "I am not a child any more, Father. I may still be your child, but I am a woman. I have already made a name for myself here."
"Why did you leave, sister?" Cersei asked and you frowned as you tried to sit up. "Because I couldn't take it any longer. The constant divide between you and Father and myself. I didn't want to argue with Father, but I didn't want you or Jaime or Tyrion to hate me either." You proceeded to explain exactly what you meant. As you spoke, your father's shoulders tensed and your siblings looked like they didn't know what to say.
For a few moments, the silence in your hut felt stifling. You waited for someone to say something. In your opinion it said a lot about your family dynamic that none of them could find any sort of retort to your accusations or any way to try and console your worries and fears. After what felt like hours, your father finally spoke again.
"We are returning to Casterly Rock." You felt your heart sink. He hadn't heard a word you'd said. "No. I'm staying here." Tyrion and Cersei exchanged a glance. The two never agreed on anything, but they agreed on this. You needed to come home. "Please, Y/N. You belong with us. We're your family. I swear, I shall do my part to make you feel like you belong. You're the best of us, Y/N. We need you," Tyrion said. Of all your siblings, he was the most eloquent. He knew what to say and when to say it.
You glanced between your siblings and your father. What would happen if you chose to stay? Would your father begin treating your siblings worse? Would your siblings grow to truly hate your father? You didn't know, but you weren't sure you wanted to find out. "I will return, but I would like for there to be a few changes." Cersei and Tyrion immediately agreed. You were the glue that kept the family from falling into ruin. They knew that. For a moment, your father merely stared at you. Finally, he gave you a singular nod. "We shall discuss these...changes on the journey."
You got up and walked over to him. "Father? I'm sorry for the trouble I caused." Before he could say anything, you wrapped your arms around him. At first, he merely stood there stiffly, but eventually he returned the hug. "Let's not dwell on it. I just want you home where you belong." You smiled before turning away and hugging Cersei then Tyrion. You grabbed your bag and headed out with them. You weren't exactly sure how things were going to work, but when you arrived at Casterly Rock and Jaime pulled you into the fiercest hug ever, you knew you were home.