RWBY:the clash of civilizations

Remnant, The world where superhumans known as Hunters exist and fight the Grimm with an element called the Dust, But what happens when suddenly, the world of Remnant merges with a planet, not of their dimension? And what happens when a world of advanced technology that had already seen enough wars is merged with a world at war? (The Earth will be completely AU with many elements taken from other works, )