- "Slavery sucks big time. Uprisings and revolutions are important because people should be allowed to own stuff, not be somebody else's stuff!"
- ―An initiate on slavery, 2013.[src]
Slavery is the subjugation of an individual, to be bought and sold by another, usually for forced labor. The Isu created humans to be their slaves, and throughout history, the Assassin Order believed that the Templars intended to return humanity to that state.
The First Civilization controlled humanity with the Pieces of Eden, through neuro-transmitters implanted within the slave race. However, interbreeding led to the birth of hybrids like Adam and Eve, who were immune to the power of these devices and later instigated the Human-Isu War.
The Templar Talal ran a slave ring in Jerusalem during the Third Crusade, taking people from prisons, brothels, and sewers to be shipped to Garnier de Naplouse in Acre, where they were experimented upon in hopes of replicating the effects of indoctrination brought on by an Apple of Eden. This operation was scuppered when Altaïr Ibn-La'Ahad assassinated both men.
During the Borgia's rule of Rome, Silvestro Sabbatini kidnapped men, women, and children to be deported into slavery. Ezio Auditore da Firenze and his apprentices assassinated him and freed those he was keeping captive.
During the Golden Age of Piracy, European powers like the British, French, and Spanish enslaved Africans to work in their colonies in North America and the Caribbean, particularly the local sugar plantations. It was around this time that the regional Templars decided against slavery, claiming that there were more effective ways to control the populace; however, Woodes Rogers refused to quit the slave trade, and was eventually expelled from the Order.  Later Templars however continued their participation in slavery; Lawrence Washington, a Master Templar in British North America, was one such man. 
In 1735, the Assassin Adéwalé was shipwrecked on the French colony of Saint-Domingue. Having been a slave before he became a pirate, Adéwalé allied himself with the island's Maroon rebellion, led by Augustin Dieufort. In the following years, he freed many hundreds of slaves from plantations and slave ships in Port-au-Prince and in the Caribbean; as such, many joined the Maroons, bolstering their numbers.
In 1754, Silas Thatcher, an officer in the British Army, began enslaving members of the Kanien'kehá:ka nation, including Kaniehtí:io. Haytham Kenway and his band of Templar brothers freed the slaves and killed Silas to gain the natives' trust.
At the start of the American Revolutionary War, Lord Dunmore offered slaves belonging to Patriots freedom if they escaped and joined the British Army. George Davidson, a friend of Aveline de Grandpré, enlisted in Dunmore's Ethiopian Regiment because of this proclamation.
In an alternate reality created by an Apple of Eden, King Washington enslaved the Kanien'kehá:ka, and later declared he would invade England to do the same. The Haitian Assassins under the leadership of Eseosa and Toussaint Louverture sparked a slave rebellion and the Haitian Revolution . At the same time the French Revolution broke out in France, Haiti's colonial master. Over the course of the Revolution, the Templar Maximilien Robespierre abolished slavery across France and the colonies, an action welcomed by the Haitian Assassins even though Robespierre, and his master Germain, were opposed and finally deposed by the French Assassins . Several years later, Napoleon Bonaparte, sent an expeditionary force to Haiti to capture Louverture and restore slavery to France's colonies. The Haitians revolted against the French, led by Charles Leclerc. In the course of the events Jean-Jacques Dessalines would come to power and establish a dictatorship, driving Eseosa to the Davenport Homestead, vowing to claim revenge .
The cultural practices involving slavery have varied greatly throughout history, both on a chronological and geographical basis:
- Gladiators - In Ancient Rome, slaves were made to fight to the death for the entertainment of citizenry.
- Military - At the dawn of the Middle Ages, several military orders were made up of Europeans enslaved as children and trained to serve their conquerors. An example of this were the Janissaries of the Ottoman Empire.
- Concubines - Around the world, people were sold into sexual slavery to serve the higher classes.
- Eunuchs - These slave guards watched over concubines, and were castrated at a young age to discourage desiring them.
- Placée brides - In French and Spanish colonies like New Orleans, a practice arose of slave owners, typically white men, selecting slaves for a form of "practice" marriage. Often though, they conceived children and opted to free their wives from slavery.
- Dalits - The lowest tier in the caste system of India, Dalits were considered untouchables and born to serve the higher castes as servants and sex slaves.
- Child labour - A pseudo-slavery employed en masse in Victorian London that saw children as young as four working in industrial factories for nominal wage.
- ↑ Assassin's Creed II
- ↑ Assassin's Creed II - Glyphs
- ↑ Assassin's Creed
- ↑ Assassin's Creed: Brotherhood
- ↑ Assassin's Creed IV: Black Flag
- ↑ Assassin's Creed: Rogue
- ↑ Assassin's Creed IV: Black Flag - Freedom Cry
- ↑ Assassin's Creed III
- ↑ 9.0 9.1 9.2 Assassin's Creed III: Liberation
- ↑ Assassin's Creed III - The Tyranny of King Washington
- ↑ 11.0 11.1 Eseosa's Codex
- ↑ Assassin's Creed: Unity
- ↑ 13.0 13.1 Assassin's Creed: Revelations
- ↑ 14.0 14.1 Assassin's Creed: Forsaken
- ↑ Assassin's Creed: Brahman
- ↑ Assassin's Creed: Syndicate