Hunterxhunter's manga / #Webtoon(1470)

The MC gets reincarnated as an extra in a novel who sister had died due to the ML. To prevent her sister dying she tries keep her sister from getting too close to the ML. The ML then takes an interest in the MC instead. The ML is an adult who was cursed to turn into a child during the day and revert back at night. It's good, the only reason that I rated it so low was because the romance was kinda eh. -reincarnation 6/10