I’m the brave puppy that will save the villainess

Woof! Sister, it’s me, Coco! My name is Coco. I’m a very nice puppy with white, fluffy fur. “If there is a next life, please be born as my sister’s daughter. Okay?” After living a happy dog life with my sister, I crossed the rainbow bridge. ‘Gasp! My sister is always crying after my death!’ No! My sister’s happy life will be protected by this brave puppy! …And so, I crossed the rainbow bridge once again and was reincarnated as a five-year-old adopted daughter in my sister’s family. But it’s not easy to get along with her. “I’m tired of meeting people, and sooner or later, I’m going to close the doors of the mansion.” I quickly raised my short hands. Then I drew the biggest circle I could manage. “I’m this strong!” So please, sister… can’t you be friends with me again? •──── ★ ────•​……I got depressed for a moment because I couldn’t reveal my identity as a dog to my sister or get closer to her. But I’m a former brave pup and now a clever little girl with a plan! I’m going to work hard to win over my sister and her family so we can be a ‘real family’. “If you want something, say it. You saved a great spirit beast, so you deserve a reward.” “First, I want you to play ball with me ……, second, I want you to swim with me, third, I want you to give me lots of sweet potatoes, fourth, I want you to make sweet potato cakes with me in the kitchen, and fifth, I want you to let me eat the chocolate you never let me eat before…….” “You pulled off one great deed and now you’re trying to squeeze everything out of me…?” “Yes!” “You’re ……ambitious.”​I even talked smart to my sister’s dad and got noticed! Step by step, I grew closer to my sister and her family. And finally, the day came to reveal who I truly was. “My Coco, you and I are going to be together for a hundred years, okay? Promise.” “…I’m not saying this because I like you or anything, but… when you’re over twenty, uh, l-let’s get engaged. Not because I like you or anything! Don’t get the wrong idea!”​My sister, my family, and even my childhood friends… they all seem to have a serious case of separation anxiety. But the truth is, I……. When I turn ten, I’ll have to return to the star where dogs go?