In 1866, Austria and Prussia fought with each other and victory ended for Prussia which eventually united with German states and fought France too. But what if in this alternate scenario, Russia joins the war to help out Austria due to fear of Prussia's power. How would that turn out?
According to historical numbers, Prussia mobilized 400,000 troops against Austria, backed by 300,000 Italians and 100,000 German allies. Austria mobilized 400,000 troops, and her allies provided another 200,000. Russia had 500,000 active troops defending her empire. 120,000 were in Asia, fighting in India, and another 130,000 in the far east, patrolling her Siberian and Chinese colonies. If her 200,000 reservists were called up she would have 450,000 troops to invade Prussia with. Prussia had another 200,000 troops facing the French across the Rhine, and another 200,000 troops defending East Prussia and Silesia from the Russians, as well as another 130,000 reservists being prepared to be thrown into service at any time.