- 阿泰尔: "你真觉得你是在帮助别人吗？"
- 加尼耶: "不是觉得……是确信。"
来到阿卡后，加尼尔买通了他的手下，让他们帮助他继续自己的残酷实验。Determined to keep any news of his crimes a secret from his superiors, he closed the hospital to only approved visitors and had patients crippled to keep them from leaving. In time, he came to believe that the patients were nothing more than lost souls in need of aid and that he had a responsibility to guide them however he saw fit.
At some point, Garnier joined the Templar Order and learned their ways and secrets just like his fellow members. What he learned included the Templar's views and even information on the mysterious artifact, the Piece of Eden.
- Altaïr: "Let go your burden."
- Garnier: "Ah, I'll rest now, yes. The endless dream calls to me, but before I close my eyes, I must know: what will become of my children?"
- ―Garnier to Altaïr, inquring about his patients' fates.[来源]
Following the siege of Acre, Garnier was granted jurisdiction of the Poor District in Acre. There, he set up his base of operation at the Hospitalier hospital, and continued his brutal experiments. Rumors of his horrible work spread throughout the city, causing civilians to fear and avoid the hospital.
When Altaïr infiltrated the Hospitalier Fortress with the intention of assassinating Garnier, a terrified patient attempted to escape, only to be captured by Garnier's guards. When Garnier revealed himself, he attempted to calm the patient with kind words. However, the patient caused an outburst, claiming that Garnier's true intentions were evil. After the doctor admonished him, he commanded the guards to break the patient's legs, knowing this would prevent another escape attempt.
When Garnier dismissed the horrified crowd and returned to his work, the Assassin stealthily made his way inside the hospital, and located the doctor. Altaïr then took the doctor's life with his Hidden Blade. With his final words, Garnier claimed that he was actually helping his patients; although Altaïr tried to rebuke all of his claims, Garnier persisted in his beliefs.
Garnier claimed that the people he took were among the poorest and most ill of the surrounding cities, and that many had recovered and were grateful for his generous help. He said his methods were necessary to free people from the "prisons of their own minds." Altaïr asked if he truly believed that he was helping them, and Garnier simply replied, "It's not what I believe, it's what I know." Before he could say any more, however, Garnier died, and Altaïr was left to escape the area, and report his success to the local Assassin bureau.
Garnier genuinely believed that he was helping the people that he held in his hospital, despite committing cruel and unjust acts to his patients, turning them into his slaves, and making them his guards. Even though he claimed to be a man of science, he completely lacked a sense of ethics and morality. He did not seem to fear death and even while he was communicating with Altaïr, he attempted to justify his actions, explaining why he dragged them from their supposed "homes" such as brothels or sewers.
He often wore black robes with an apron that was stained from the blood of the patients who had been involved in his experiments. He had a small leather belt around his waist which held up a small pouch and he usually carried his sword around with him for protection. He was of average height and weight, with signs of aging, such as wrinkles and balding being prominent in his appearance.
- Like Sibrand and Robert de Sable, Garnier was a historical leader of the Knights Hospitalier, serving as Grand Master from 1190 to 1192.
- Historically, Garnier de Naplouse fought in the Battle of Arsuf, while in Assassin's Creed, he died before the battle took place.