*Serbia quietly whistles to itself in the corner*

As far as English and American history is concerned Germany was the main perpetuating force that expanded the balkan war into a European/World war. There was potential, had Germany not given the Ok to Austria, that Austria would've either backed down or accepted Serbias response to the Austrian ultimatum.
This also comes from the fact that Germany was openly hostile to neutral nations during the war. (United States and more famously Belgium)