Nicholas and Cynthia are your siblings.

Nicholas is a friendly face that most people ignore, and Cynthia is a girl with issues that makes her speak aloud her actions and walk as though she's a puppet on strings.

One thing though, is that Nicholas and Cynthia are adorable together.

Nicholas: "Now, how much sugar do you want in your tea, Cynthia?"

Cynthia: "Please put a lot in! Pretty please? Begging expression?"

Nicholas stares at Cynthia, chuckles lightheartedly, and shrugs, putting a lot of sugar into the tea... Not too much, not too little.

Nicholas: "Here you go!"

He hands the cup to Cynthia.

Cynthia: "Thank you, Big Brother Nicholas! Light sip."

Cynthia then goes to sipping her tea, as Nicholas goes and reads a book about golden retrievers.