you were Rui's younger sibling. he liked your company, since it made him feel a little less out-of-place.

while Rui was building a small robot for you, you entered his room, causing him to hide it behind himself.

"hey. what're you doing in my room without knocking?" Rui asked jokingly, a grin on his face that slightly showed his worry for if you'd see his unfinished work.