Do you want to play a game with me? Whoever loses will be the king of this house,agree?

Yuna Watanabe,He is my half-sister since my father married his mother, to be honest, I am a bit uncomfortable with his behavior because he is always nosy with me and it annoys me with his behavior.But even so, he is still my sister and I have no other choice but to accept his presence in my life even though it sucks for me