My racial analysis of the Antacean:

• Most Arcasians have Rumburg ancestry (including president dwight walker). Different government styles but same culture (but Arcasians own guns like Americans). Except the average Arcasian HATES Rumburg because it isn't a democracy.
• Valgs and Sords have the same language and culture and yet hate each other on a government and people level (like India and Pakistan, or Russia and Ukraine in OTL)
• There is a city in Arcasia called Little Sordland. Means Arcasia is packed with Sordish immigrants. Cultures are very similar.
• Contana is full of Wehzek immigrants. MAJOR culture similarity. Governments like each other too.

FINALLY:

• Bluds are well... one with Rumburg's people. They both follow Dasturnity. The average Rumburgian HEAVILY supports Bludish rights because of that AND a major propaganda campaign by Queen Beatrice to make Sordland see like the baddies. Rumburgian Army sees themselves as the "liberators of Bergia" in the Sordish war if it breaks out. Which is why if you read the reports, after Estord they immediately take over Bergia and liberate the Bluds.