Do you have a novel that you recommend? It's about a woman and her master traveling through time and space to complete a mission. There's also a story about a senior brother appearing? I've seen it before, but I want to read it again.

Perhaps it was the book," Quickly Wear It to Find Happiness." The female protagonist had a tsundere system as her companion. Her mission was to travel through time and space to complete various missions. Sometimes, she needed to be a character. She also has a master and a senior brother, but the details are different. Perhaps you remembered wrongly. However, this book was more interesting. He might as well read it again. He might find a new feeling. I hope my recommendation can help you. If you like this book, feel free to tell me.