Animus Subjects

Subjects are people who have been selected by Abstergo Industries for use in their experiments with genetic memory and the Animus. There are (or have been) at least seventeen Subjects, of which only 3 are ever mentioned in Assassin's Creed. Also, unfortunaltly sometimes if the subject becomes worthless with memories they get killed by the employes.

Known Subjects
Only subjects 12, 16 and 17 are ever mentioned in the game. Subjects 1 through 15 besides 12, as well as any that may exist after 17, are never shown and never seen.

Subject 12
Subject 12 was the direct descendent of an indivual involved (or subjected to) the Philedelphia Experiment, a popular conspiracy theory where a naval vessel is alleged to have travelled toward in time for 18 minutes. The email claims that the Templars obtained sufficent information to reconstruct the device responsible, but will not continue with development due to concerns about the creation of irreparable time paradoxies.

Subject 16300px-Crypticmessages.jpg
Subject Sixteen was the predecessor to Desmond Miles in Abstergo's experiments. His name is unknown, but he is at one point referred to as "Neumann". He is never seen in any game.

It is known that, due to the "Bleeding effect", Subject 16 went mad and wrote the cryptic messages throughout the Animus room and his bedroom, using his own blood (dying afterwards). He may also have, in his madness, murdered Leila Marino and used her blood to write some of the cryptic messages as it is even stated by Subject 16 himself that if he would have written all of the messages with his own blood, he would have died before he finished.

Subject ? (Daniel Cross)
Daniel Cross was a recovering alcoholic and drug user who was brought to Abstergo to relive the memories of his ancestor, Nikolai Orelov. Not much is known about Daniel at this point. One of the writers of the Assassin's Creed comic book mini-series mentioned that Daniel plays a very significant role in Assassin's Creed and Assassin's Creed II, possibly meaning that he is Subject 16. However, this isn't confirmed at this point.

Subject 17 (Desmond Miles)
Desmond Miles is the true protagonist of Assassin's Creed.

Brought to Abstergo against his will, he was threatened with a coma and death if he did not participate in the Animus project. Giving in to the threat, he entered the Animus. He was made to recreate the actions of his ancestor Altaïr, in order to find the location of the Piece of Eden. Like Subject 16 before him, Desmond experiences the Bleeding effect. However, he only experiences a relatively minor change- the ability to use Eagle Vision like his ancestor. This is probably due to Lucy urging him to take breaks from the Animus. In Assassins Creed 2 though he gains all of Ezio's skills. In Assassin's Creed Abstergo were about to kill him until Lucy suggested that he can still be useful for finding more Pieces of Eden.

Assassin's Creed: Brotherhood
It has been noticed in the multiplayer walkthrough video that the players in the game are referred to as "Subjects" e.g. "Subject 6 killed Subject 2". This could likely be replaced with player's gamertags when Assassin's Creed: Brotherhood goes live.