Yuffie can now explain things to herself, proving one thing.
Even people who haven't been to school have heard of the famous area of Syndicate, just like everyone knows about the empire.
The crown princess obviously thinks that he comes from "outside" and doesn't understand their world, which is why she spoke up.
In other words, "Teacher Reji appeared at the most appropriate time and place. Besides being a demon, I can't think of a second possibility."
"But I killed a demon just now," Reji asked with interest.
Yuffie shook her head: "For the sake of becoming the queen of Ilinor, all the royal family members, including my father became my sacrifices tonight. In comparison, I think Teacher Reji has been very merciful."