The Crusaders are undeniably English. The red and blue color scheme, the Lion Or on Azure, it can't be anything but English.
The Forestmen hold a special place in my heart as Celtic. More Ireland, less Sherwood Forest.
The Dark Foresters strike me as Welsh; resembling Forestmen but without as much flamboyancy.
The Wolfpack would be Scottish Highlanders; conquered but not destroyed, and resisting and undermining the Crusaders at every turn.
The Black Falcons are more Germanic; cold and rather intimidating. They have a huge 'Don't Mess With Me' aura, and I don't see Germanics as pushovers.
The Black Knights would be in southern Europe, encompassing Italy, Austria, the Czeck-Slovakian area, Hungary, Croatia, Bulgaria, Greece, Poland, Serbia, and even ranging into Turkey. Their colors, which are largely different while keeping a central unity, and their numbers, which are staggering, suggest a wide empire varying in culture.
The Royal Knights are Spanish, mostly because of the awesome mustaches.
The Bull Knights are in the Swiss area, hiding out in the mountians and daring adventurous fools to tresspass.
The KKI fellas would be Portuguese; their one real soldier looks a lot like the Spanish fellas without giving the impression of as mighty an empire.
The Dragon Masters are from Northeastern Europe, from Romania to Estonia, as they have the flamboyancy and wildness suggested by the Transylvanian legends.
The Fright Knights are Russian; grey, mysterious, foreboding, and often portrayed fighting the Dragon Masters.
The Vikings are Scandinavian and Danish, obviously, and the Ninjas are Oriental, even more obviously.
The new Crown Knights are French; the Crown emblem (somewhat resembling a Fleur-de-Leis) and the dark blue uniform with scale mail seem French-ish to me.
The Shadow Knights are from Belgium and the Netherlands, as they are the principal enemies of my Crown Knights and (imaginary) Black Falcons. Actually, Belgium and the Netherlands hadn't yet been taken and the Shadow Knights were too cool to be left out.
The Jelly Knights are from California, the only place they can visit without being laughed at (often).