Vitae is a mystical substance that is secreted in the blood of mammals during times of great stress, such as torture. Alexander of Brennenburg used various methods of torture on prisoners in order to produce the vitae he needed to return home.
Vitae is of cosmic origin and causes the living host to burst with energy. The catalyst is produced somewhere in the brain. Although many of its properties are unknown, one of them is the ability to extend life, potentially for centuries, if consumed in large amounts. In order to procure such amounts, it must be acquired from humans. Alexander found out through torturing dogs that although animals also secrete Vitae, they do not produce it in large enough doses to be of any use (See Canis Lupus Familiaris Note).
Obtaining Vitae is a methodical and painstaking task, as torture must be inflicted in the right fashion for maximum Vitae extraction. When pain or fear is instilled in a victim, the body fills the bloodstream with Vitae, and this can result in fits of violence and brute strength if the victim is not properly restrained and terrified. After the victim is completely broken, they will no longer produce enough Vitae, as their mind has already adjusted to the torture. Thus, Alexander used an amnesia drink to make them forget about the torture, so more Vitae could be harvested.
Alexander made several attempts to create an artificial form of Vitae in the Laboratory. However, each one ended in failure. The otherworldly being was unable to grasp the mysterious inner workings of life and their relation to the mystic energy. His last experiment's chemical solution was rendered highly acidic and useless for the intended purposes as it ironically dissolved organic matter instead.
After the events of the dark descent 60 years later, Oswald Mandus discovers the effects of Vitae after witnessing a worker's severed head come to life after being drenched in the ''Brennenburg compound'' and starts using vitae in his experiments. Calling it Brennenburg Infusion Vitae, he uses it in conjunction with another substance, the Orgone Monad Disperal fluid to create his Manpigs. It is unknown whether Mandus discovered vitae on his own or simply continued and improved on the work of Alexander of Brennenburg.
- The Vitae from Amnesia: The Dark Descent shares a slight resemblance with "Azoth" from Haunting Ground. Both Vitae and Azoth are extracted from tortured humans, and occasionally animals, and can extend one's life for centuries. The tortured victims will most likely die from the extraction.
- "Vitae" translates to "Life" in latin.
- Alexander's attempts to recreate Vitae might hint at it being ethanol, which was called aqua vitae ('life water') by alchemists around that time period. Ethanol occurs in the mammal bloodstream, and can dissolve organic matter.
- Many of the effects of vitae (such as increased strength in stressful situations) are caused by adrenaline in the real world.