She came to the world to find her sister's soul; her blood can open the flowers sealed by ice and snow; every time she goes to a world, she will seal her feelings, just because she doesn't want to be a burden...
When she completed the task through rebirth for the first time, she discovered that the feelings between people were more difficult to understand than what her sister said back then, and she also understood where her sister's nostalgia for the world came from...