The Knights Hospitalier were one of the several knightly orders founded during the Crusades, and were tasked to provide care for the sick and wounded in the Holy Land.
By 1191, the Knights were led by Garnier de Naplouse, who was secretly a Templar. He experimented on his patients to try and replicate the effects of the Apple of Eden. He achieved a limited amount of success, though he was assassinated by Altaïr Ibn-La'Ahad, which ended his experiments.
By the Renaissance, the Hospitalier base had moved to Rhodes, and the knightly order were responsible for killing the Master Assassin Castor. In response, Ezio Auditore da Firenze sent a team of Ottoman Assassins to burn the Hospitalier compound to the ground.
- The Knights Hospitalier were the only faction of Crusaders without high-ranking soldiers, aside from informant targets.
- In Assassin's Creed, the armor and uniform of Knights Hospitalier guards was strikingly similar to that of the high-ranking Templar crusaders in the Holy Land, with the primary difference being the black and white coloring of the Hospitaliers, as opposed to the red and white of the Templar crusaders.
- In Assassin's Creed: Revelations, the simulated location of Rhodes in the Animi Training Program contained a Knights Hospitalier fortress. In reality, during the 15th century, the Knights Hospitalier held sovereignty over the island.
- Hospitalier Captains could be seen behind King Richard in the crowd when the latter was confronted at Arsuf, and during some of the investigations conducted by Altaïr.
- The Hospitaliers still exist as the Order of Saint John, although they no longer serve a military function.