The Teutonic Knights are one of many idealistic factions mentioned by General Artyom Orlov during The Commander's diplomatic visit to Moscow.
According to Orlov, they are based in Post-War Germany and are currently at war with The Fourth Reich who are also based there.
They seem to be the continuation of the historic/present day order or are at least based off of it, but other than that little else is known about the Teutonic Knights.
Country mentioned in TSC Map - Known Polities of the World, TSC Map - Known Polities of the World Updated 1, TSC Map - Known Polities of the World Updated 2, TSC Map - Known Polities of the World Updated 3, TSC Map - Known Polities of the World Updated 4.
Its capital city is Munich.