The Crusades: 6,000,000Thirty Years War: 11,500,000French Wars of Religion: 4,000,000Second Sudanese Civil War: 2,000,000Lebanese Civil War: 250,000Muslim Conquests of India: 80,000,000Congolese Genocide (King Leopold II): 13,000,000Armenian Genocide: 1,500,000Rwandan Genocide: 800,000Eighty Years' War: 1,000,000Nigerian Civil War: 1,000,000Great Peasants' Revolt: 250,000First Sudanese Civil War: 1,000,000

TOTAL: 195,035,000 deaths in the name of religion.

Jewish Diaspora (Not Including the Holocaust): 1,000,000The Holocaust (Jewish and Homosexual Deaths): 6,500,000Islamic Terrorism Since 2000: 150,000Iraq War: 500,000US Western Expansion (Justified by "Manifest Destiny"):20,000,000Atlantic Slave Trade (Justified by Christianity): 14,000,000Aztec Human Sacrifice: 80,000AIDS deaths in Africa largely due to opposition to condoms: 30,000,000Spanish Inquisition: 5,000TOTAL: 195,035,000 deaths in the name of religion.

German Peasants' War - A series of peasant revolts during the height of the Protestant Reformation, spurred on by a mix of economic and religious causes. 100k deaths for Christianity.

Moro Insurgency - Islamic rebels in the Philippines have a long, bloody history of resistance against colonial and Philippine governments alike. 120k deaths for Islam.

Northern Crusades - Crusades to root out the Baltic pagans. Couldn't find any good casualty estimates, but 150k deaths for Christianity seems reasonable.

Algerian Civil War - More Islamist rebels. 200k deaths for Islam.

Lord's Resistance Army - Christian militants in Central Africa. Remember Kony 2012? 200k deaths for Christianity.

Albigensian Crusade - France leads a crusade to root Cathar heretics out of the Languedoc. Estimates vary wildly from 7k to 1mil, but let's just say 200k deaths for Christianity.

Great Turkish War - A "Holy League" of Christian states rolls back the Ottoman Empire's conquests in Eastern Europe. 300k deaths for Christianity.

Afghan Civil Wars - A variety of Islamists, including Al Qaeda, vie for control over Afghanistan. 400k deaths for Islam.

Rashidun Conquests - The Islamic Caliphate conquered its way from being a desert backwater to the world's most powerful state in an incredibly short period of time. I can't find anything resembling an estimate for the casualties involved, so I'm going to completely BS this one: 500k deaths for Islam. Trust me, it won't affect the winner.

Ottoman Conquests - Mehmed II leads the Ottomans on a merry path of conquest over Eastern Europe. 800k deaths for Islam.

The Crusades - All of Christendom spends a few centuries banging it's head against a Holy Land-shaped wall. 1mil deaths for Christianity.

But three wars that most people have never heard of completely blow this competition out of the water.

French Wars of Religion - The French Protestants and Catholics spend 36 years massacring each other silly. 3mil deaths for Christianity.

Thirty Years' War - Protestant and Catholic princes duke it out for control of the Holy Roman Empire (modern Germany). War is waged between mercenary companies that loot the countryside to support themselves. One third of Germany dies. 10mil deaths for Christianity.Taiping Rebellion - Hong Xiuquan was born into a poor family in southern China. In 1837, he fails the imperial civil service examinations-- his only hope of getting ahead in life-- and has a nervous breakdown. Long story short, he reads some pamphlets from Portuguese missionaries, gets some freaky visions, decide's he's Jesus's younger brother, rounds up some followers (known as the God Worshippers), and launches a rebellion against the Qing Dynasty that results in the deaths of over 20 million people.