The first thing they saw was the scythe. Always the scythe. They almost missed the boy with his book. It was a book after all, not nearly as threatening as the girl who wielded the scythe.
But they were always a pair. Always together. And when they were in action, everyone disappeared quickly.
For the girl was harmless on her own. Relatively, compared to the devastation her brother created. When the scythe swung, the book was opened. When the book was opened, the boy chanted. When he chanted, the girl attacked.
And when they were done, the battlefield was cleared.