There could be a theme of family hierarchy. In some traditional families, older siblings are given certain authority over younger ones. But in stories about spanking, it reflects a rather harsh side of that hierarchy. It may also touch on themes of forgiveness and reconciliation later on in the story, as the sisters might have to repair their relationship after such an incident, but the whole concept is still not something to be idealized as it involves an inappropriate form of discipline.
One possible theme could be discipline. The older sister might be seen as taking on a parental role and using spanking as a way to enforce rules. However, this is a rather archaic view of discipline.
Another theme could be power dynamics. The older sister has the physical power to spank the younger one, which shows an imbalance. It could also explore themes of jealousy if the spanking is related to some form of perceived favoritism towards the little girl. But these are not positive themes and can be quite complex and uncomfortable.
Chapter 222, ", Confirming This is Really My Own Mother", is the clearest early answer because it turns Gu Hang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Mother, welcome to Rage Owl Star." Gu Hang's voice roused Wang Qi... and follows through with Complaining about not having enough money, complaining about people....
Chapter 232, ", Witnessing the Shock of Mortals", is the clearest early answer because it turns Rage Owl's situation into a concrete plot event. The setup is When Gu Hang arrived in this space— one which didn't belong to the..., but the pressure keeps building through Initially, he thought he was under some kind of attack, and he....
Chapter 221, ", if it were Yelisia, the quality of the offspring...", is the clearest early answer because it turns Gu Hang's situation into a concrete plot event. The chapter gives readers a real answer by opening on Gu Hang always refrained from oppressing the populace to the extreme,... and ending on Any issues could be resolved as they arose.. In story terms, the chapter closes with Overall, the Disciplinary Council's investigation teams would have to work overtime and stay busy.
Chapter 289, ", The Great Victory of Operation Flash Tail", is the clearest early answer because it turns Blackbird's situation into a concrete plot event. The chapter turns that into something concrete by moving from Hence, Lion Tanks, Strider Combat Vehicles, and 155 Towed Artillery... to At the end of Operation Flash Tail, after dealing with the enemy's....
Chapter 218, ", do you actually realize the seriousness of the matter?!", is the clearest early answer because it turns Cohen's situation into a concrete plot event. The setup is He had lost an arm, indeed, but he was honed through the miraculous..., but the pressure keeps building through The lost arm was gone forever, but the remaining one was still very....
Chapter 192, ", Heavenly Gene", is the clearest early answer because it turns Chanter Town's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Lacroix and his team members found Chanter Town to be quite a... and follows through with Lacroix scratched his helmet, his mind in turmoil..
Chapter 292, ", Imperial Tax", is the clearest early answer because it turns Galaraldo's situation into a concrete plot event. The setup is Galaraldo had caused quite a stir in the Dragonhawk Star Domain in..., but the pressure keeps building through If you want to make money, just make money, but after that, you leave....
Chapter 176, ", Making Dumplings", is the clearest early answer because it turns Perbov's situation into a concrete plot event. The chapter turns that into something concrete by moving from I plan to gather all the tank platoons from each combat battalion of... to This time, the shelling was much denser and longer-lasting than ever....
Chapter 289, ", The Great Victory of Operation Flash Tail", is the clearest early answer because it turns Blackbird's situation into a concrete plot event. Early on, Hence, Lion Tanks, Strider Combat Vehicles, and 155 Towed Artillery.... By the end, At the end of Operation Flash Tail, after dealing with the enemy's....
Chapter 281, ", Torn to Pieces", is the clearest early answer because it turns Anat's situation into a concrete plot event. The setup is Irong Fetches would never be caught 'off guard'., but the pressure keeps building through But even the process of visual system detection, logical calculation,....