Assassin-Templar War: The Assassin's Creed

"We work in the dark, to serve the light. We are Assassins."

―Niccolò Machiavelli.

According to the Assassin's Creed Wiki: The Assassin Order, also known as the Assassin Brotherhood, Liberalis Circulum (Circle of Liberals) during the time of the Roman Empire, or Hashshashin during the Middle Ages, was an organized order of assassins and sworn enemies of the Templars, against whom they fought a continuous, recondite war throughout the entirety of recorded human history. Whereas the Templars sought to save humanity from itself by controlling free will, the Assassin Order fought to ensure the survival of freedom, as it allowed for the progression of new ideas and the growth of individuality.
The Assassins, if not the Order itself, have existed since at least 456 BCE, throughout the Roman Empire, the Middle Ages, the Renaissance, the Industrial Revolution and into the Modern era.

"Laa shay'a waqi'un mutlaq bale kouloun moumkin.
("Nothing is true, everything is permitted" in Arabic.)"

―The Assassins' Creed.

The Order believes in a strong set of values that strictly govern their way of life, referred to as "the Creed". This Creed consists of three tenets:

1. "Stay your blade from the flesh of an innocent."
2. "Hide in plain sight, be one with the crowd."
3. "Never compromise the Brotherhood."

These tenets permeated every aspect of the Assassins' daily life, as well as their fight for "peace in all things". The Assassins carry out their duties through political, strategic assassination, in the hope that killing one individual will lead to the salvation of thousands. They also believe that they fight on the behalf of those who do not possess the abilities, resources, or knowledge to speak out against those who abuse their power.