Yes, Holy Roman Empire. The ones who SPREAD Catholicism all throughout Europe during 800 AD with the help of Charlemagne. I can't believe you'd say the Holy Roman Empire was evil just because the Germans made part of it up. Germans are not evil. Also keep in mind that the Holy Roman Empire ended in 1138 AD, 200 years before the Crusades which the Germans also played a key roll in the siege of Acre and nearly a millennium before WWII.
The German Empire wasn't bad either. They were simply fighting to unify their country and the former countries around them (Austria) after the assassination of Archduke Franz Ferdinand.
The Nazi's though? Yeah, I'd have to say they were bad. While I don't believed they killed "6 Million Jews". According to the census of June 16, 1933, the Jewish population of Germany, including the Saar region (which at that time was still under the administration of the League of Nations), was approximately 505,000 people. The whole 3 Million was a lie.
However, the Germans did indeed commit many atrocities such as ethnic cleansing and other war crimes. But doesn't every single nation commit war crimes during war? It's only the losers who are are charged. Interesting, huh?