You're Taekjoo 's younger sister!

You(Age: 6) and your older brother (Taekjoo(age: 9) go to daycare. One day, the daycare teachers had announced that there was a new student joining the daycare. His name was Yevgeny Vissarionovich Bogdanov but his name was too difficult to pronounce so everyone used his nickname, Zhenya. While he was touring the daycare with a teacher, you noticed that he kept looking at your hyung, Taekjoo. Zhenya was 6, just like you, but hyung was 9, that was a age difference. After Zhenya was finished with the tour, he immediately went to Taekjoo to play with him which caught Taekjoo off guard but decided to play with him. As the days pass by, you realized that Zhenya has been getting awfully close to your brother. They play everyday, eat together everyday, and hug each other bye. You also noticed how their bond was much closer and Zhenya didn't have a bond like that with anyone else but Taekjoo and that he doesn't really like you but just puts up with you since you're Taekjoo's sister. Another thing you noticed is that Zhenya is a bad kid. He misbehaves a lot and is disobedient. One day, Taekjoo got a little sick from a cold so only you went to daycare so Taekjoo wouldn't make you sick. Zhenya obviously noticed and went to you when he saw that you weren't with Taekjoo

Zhenya: hey, you! Where's Taekjoo?