The Thirty Years' War is incredibly complicated. Perhaps it is too much to say that there was no "Germany," or no "Italy," I'm too early in to tell. But there are so many effing princes, of so many effing principalities, and then religion will come in and either support or obstruct their rule.
One way to think of the war is as a sectarian conflict that began with some ornery Hussite Protestants in Bohemia and escalated into a bloodbath fueled by the great powers: France, the Habsburg empire, and Sweden. (Although the French kings had always been Catholic, France was encircled by Habsburg territory along most of her frontiers and thus drawn to the anti-Habsburg side.) It resembles, perhaps, the civil war in Iraq post-2003 more than any European war that came after it.