Lena learns the truth about the upcoming end of the war, and how the Legion is a much more deadly threat than she though.
So the reason you know 
when the Legion are coming...
...إذا فالسبب الذي يجعلك تعرف موعد وصول الأسطول
Quindi il motivo per cui riesci
 a prevedere l'arrivo della Legione...
Então, o motivo de você saber
quando a Legion está vindo...