Jaime had always held a soft spot for Myrcella. He'd heard it was natural for a father to care deeply for his children but that instinctive sense of paternal devotion had failed to rear its head the night of Joffrey's birth. He had stayed by Cersei's side throughout the entirety of their son's birth, despite frequent attempts to remove him from the birthing room, but when the screaming infant had finally arrived into the world it had taken mere minutes for the boy to instil an irrational sense of jealousy in his biological father. His sister's attention seemed to rest solely on the blonde infant in her arms and for the briefest of moments he had worried that there would be no more of it left for him. Then when he had asked to hold the boy she had quickly turned him away, muttering something under her breath about having created too much suspicion already. That was the moment he had lost all interest in Joffrey. For all he cared, Robert was welcome to the boy.
The morning of Myrcella's birth had been a different occasion, however. The guards had once again protested against his entry into the birthing room and Jaime had once more enquired as to which one of them proposed to keep him out of it. He'd been by her side, watching as Cersei struggled through the early hours of the morning in labour and into the daylight. Myrcella's birth had proved more difficult than he had remembered Joffrey's being and at one stage he had been forced to enquire as to whether everything was alright with the baby. Another hour passed before his anxiety was put to rest and the cry of an infant girl broke the otherwise silent room. The child was taken away from her mother briefly as the maids set about c wrapping her in cloth before handing her back to Cersei's capable hands. Exhaustion had clearly taken its toll on his sister but somehow her beauty still managed to remain, so much so that Jaime couldn't help but stare as she gently rocked the babe in her arms. The same pang of jealousy he had felt shortly after Joffrey's birth had sparked from somewhere in his chest but this time it was quickly replaced by a strange sense of affection for the child. The minute Cersei's eyes began to droop, Myrcella was taken from her arms and put to rest a few feet away from where she lay in bed. Both child and mother had quickly drifted off to sleep and the maids soon after made their exit, leaving Jaime to stand watch over his sister and their daughter. He'd quickly lost track of time, unsure of how many minutes had passed before Myrcella had stirred and awoken with a soft cry. Having had nothing to do with Joffrey, Jaime's knowledge of babies was limited at best and he had made the conscious decision to leave Myrcella be for his sister to care for when she awoke again. Unfortunately, the young girl had other ideas and swiftly broke out into a continuous wail. Unwilling to disturb Cersei's rest, he was forced to attempt to deal with the child himself. Several minutes of awkward fumbling later and he had found himself cradling a newborn Myrcella in his arms, rocking her as gently as he could manage until she slowly drifted back off to sleep.
That had been the beginning of his unconventional relationship with his daughter. Naturally the entire world had been led to believe that she was the spawn of Cersei's damnable husband, including Myrcella herself, but he knew better. Provided he kept any public displays of affection towards the girl to a minimum, Cersei tended not to chastise him for his fondness of her. If nothing else, their shared love of Myrcella seemed to draw the twins closer together. Some of the time.
"And now you're dead." Jaime remarked with a smirk as the wood of the small sword in his hand came to rest gently against his daughter's neck. Myrcella huffed and folded her arms across her chest, the wooden sword in her hand clattering to the floor as she sulked in her defeat. With a laugh, Jaime noted just how alike she was to her mother in that moment. "Now… don't sulk. Pick up your sword and try again." He encouraged as he gave the young girl a light nudge with the wood of his blade. Myrcella's small fingers had barely grazed the handle of her sword when Cersei's voice sounded from the doorway off to his left. "What have I told you about encouraging her to play with swords? She's a princess, not a common sellsword." With a sigh, Jaime settled the wooden sword in his hand down at his side and turned slowly to face his sister with a smirk that reeked of arrogance. "Come now, sister. You can play too if you ask nicely." He teased her, sparing a brief glance at Myrcella before turning his mildly amused expression back to a much less so Cersei. Her hard gaze met with his briefly before she softened her expression and turned to look upon her daughter. "Myrcella, go change for dinner. Your father will be gracing us with his presence this evening and you know how he gets when anyone arrives late." She neglected to add that Robert himself was usually the one to show up half an hour late, reeking of some common whore and half a brewery's worth of alcohol. On the rare occasions he bothered to dine with his family, she was usually forced to endure his sweaty, disgusting body heaving on top of her after the meal had finished before he finally spent himself inside her and passed out for the remainder of the night. The prospect was enough to have put her in a foul mood already.
Myrcella didn't need telling twice and with a tentative glance in her uncle's direction, quickly hurried from the room. Once alone, Jaime made a beeline for his sister and promptly wound his arms around her waist. "You ought to lighten up a little, sister. All of this worrying is making you look older than your years." Jaime jibed at her with a lopsided smirk as his arms moved to pull her flush against his chest. Cersei's hands came up to rest against his torso, effectively keeping some degree of distance between them as she shot him a glare. "This isn't funny. You've got to start taking more care – people are already starting to gossip over how much time you spend with Myrcella." She chastised him firmly whilst he seemed to ignore her every word in favour of finding distraction in the soft expanse of skin at her throat. She protested rather weakly with her hands against his chest. "Jaime, no- we can't. Anyone could walk in." Her voice sounded half-hearted even to her own ears but it was a charade they always played. He would attempt to coerce her into letting her fuck him wherever they happened to be at the time and she would protest, rambling on about the danger it could put them both in despite knowing that she was powerless to say no, until he silenced her with his lips on hers and her protests died with what little self-control she possessed around her brother in the first place. She lasted a whole minute before succumbing to the heat of his lips upon hers.