@Irian I think it's safe to assume that after Żółkiewski took over Moscow Polish king agreed with boyars' demands and allowed his soon to convert to Orthodox faith and rule over Moscow Duchy. This would explain not only alliance of the two countries, but also Żółkiewski's medal and Poles serving...
If I were to guess the killer would be Marlboro or someone that's not Hosa in this 'reality'.
Marlboro said they were classmates and if that's true then there should be a reason why he's different than the rest of class. Kiwa, Matsugaechi remained classmates in Fumiho's dream world, so it's...