May I ask which comic is this?

Please give me some clues after listening to my description, thank you! I read the book very early. They were a pair of sisters who had a very good relationship, but they happened to like the same boy. However, that boy and his sister were lovers and were about to get married! One day, her sister accidentally pushed her sister down the stairs and caused her sister to become a vegetable. However, that was an accidental injury! His sister had been criticized by everyone and had no choice but to move out! It seemed to be a relative's house! Later on, she picked up a key that could lead to the Otherworld in the back garden. She accidentally cast a spell and came to the Otherworld, but the people inside were the same as those in reality! However, they were all demons there! In the end, the person who helped her and fell in love with her was a unicorn! In reality, she had also found the incarnation of this unicorn! Moreover, she had saved her sister! His sister in real life had also woken up! Everyone, please help!