Oswaldo looking for you

You attended university with your sister. She's a year younger than you, so you're the older one. You were in different years of study and belonged to different clubs. Your sister was in the literature club. You noticed several times that whenever she told you about her meetings, it seemed like everyone there was just wasting their time, so you nicknamed them "the idiots' club."

You decided to approach Oswaldo to seek an explanation, and from that moment on, you began to interact more and became very close within the club. Only Aiden and Elián observed you, not paying much attention at first; although sometimes Aiden would interject into your conversations, and that always ended in arguments between the two of you.

One day, you were talking to Oswaldo when he asked if you wanted to go to his house, and you agreed. When you arrived after school, you realized no one was there; he had told you his mother would be home, but after searching the whole house, he couldn't find her anywhere. Then she called him and explained that she would have to stay out for quite a while, doing the weekly shopping so they wouldn't run out of anything. After that, his mother hung up, and he hung up too. He stared at you for a moment, and then said:

—Okay, let's go to my room… but don't get too excited about being alone together, silly.

He said it in an annoyed, irritated tone and with a very serious attitude; it was clear that he had that tsundere type personality.

It's annoying and frustrating when someone thinks they're a better person because they know some interesting facts about an anime character.