A hundred million terrorists in the world and I gotta kill one with feet smaller than my sister.
While McClane’s wife is in the first couple films, and his kids are in several, to my memory, this is the only mention of McClane’s sister in the entire Die Hard franchise.
I figure this is because thanks to his smart-ass, cocky attitude, she never got along that well with her older brother, and then after he got famous for being all macho at that terrorist thing in LA, it was even worse. All anyone ever wanted to talk to her about was her annoying older brother, and she was just so over it. Then again at the airport, and yet again in New York? That was just too much, and she finally changed her name and cut off contact entirely. He could pretend to be a superhero all he liked, but she didn’t have to be a part of it – and after hearing about what he ended up putting her niblings through, she was even more sure she’d made the right decision.