Tenets
The Tenets are the rules of the "Assassins Creed" the Assassins Order strictly live by:
- 1Stay your blade from the flesh of the innocent.
- 2Hide in plain sight.
- 3Never compromise the Assassins Brotherhood (in other words Don't ever endanger other Assassins in any way, shape or form through your actions).
Altaïr breaks all three tenets of the "Assassins Creed" during a mission in Jerusalem, and in the process was stripped of all his rank and dealt a timely ego blow. But it is the "Assassins Creed" that helps Altair realize his inner peace and guides him away from at first arrogance,impatience, and self pride to becoming a more calm,patient,listening,subtle demeanor possessing Assassin becoming that much wiser, focused....and lethal. If you kill an innocent you will lose some 'health' (a testament of what happens for breaking the strict tenet) as it partially desynchronizes Desmond. If you kill too many innocents the desynchronization becomes too great and the screen will say: desynchronized, reason: killing innocents; first tenet.
There is also an achievement you can unlock if you don't break any tenets throughout the game.