Guilty Gear Strive: Dual Rulers takes place in a world powered by magic, after human advancements in science and technology declined. The invention of Gears, biological weapons, led to a rebellion against humanity, known as the Crusades, resulting in significant losses and lasting emotional scars. At a wedding ceremony between human Ky and Gear Dizzy, their son Sin, a half-human half-Gear, is present, marking a significant milestone for interspecies relationships. However, the celebration is disrupted by the arrival of a young girl who harbors intense dislike for Gears.