What did cause the war between Marleyans and Eldians? I'm finding answers for my book. It's about a war between Marleyans and Eldians but it did not tell in the manga what caused the war so I was looking for some help.
Major manga spoilers below!


   After obtaining power of Titans, eldians started massive ethnic cleansing, and marlians became one of the victims of this act, naturally inflicting massive hatred towards eldians.


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