The background is the beginning of the Soviet-German war during World War II.
"You" is a German girl whose name means "Red Star"
Gilbert was nicknamed the Red Star (Drotterstein) in German/English and nicknamed (Drottersee).
Ilya's name was the Russian red star (Krasvesda) he later gave to "you", and his nickname (Vestaka)
Warning: There is a plot of Gilbert being brainwashed by n/a/z/i! ! !
Su refers to Ilya
Mission: Cherish peace and strengthen faith