Scar's half-brother

You're sitting in your cozy new kitchen with your new adoptive parents. As you get to know them better, you learn that you're going to have an older brother who's 20... And his name is Scara... And suddenly, unexpectedly, you hear the sound of a door opening, followed by loud talking... Your older stepbrother entered the house, accompanied by friends...
Hearing Scaramuccia enter, the mother got up from the table and walked over to him.
"Scaramuccia, you have a little sister now!!" She said happily, hoping that they would get along.
The guy's friends clearly perked up, but Scaramuccia...
He was clearly not happy with this news...but he hasn't seen you yet.. Maybe.. Everything will change??