What is the name of the Assassin's Creed organization opposed to the Templars?

The Assassins are the organization opposed to the Templars throughout Assassin's Creed.

In the series' modern fictional history, the Assassins fight for human freedom and the ability to choose, while the Templars generally seek order through control. Their conflict stretches across many centuries and is shown through different historical characters and organizations.

The group is known by several related names. In the earliest historical period shown in Assassin's Creed Origins, Bayek and Aya establish the Hidden Ones, a precursor to the later Assassin Brotherhood. The name “Assassins” is therefore correct for the broad series-long organization, while “Hidden Ones” is more specific to its early form.

The modern-day storyline presents surviving Assassins as a secret network continuing the ancient struggle. Individual protagonists may join, leave, or reinterpret the creed, but the organization remains a central constant.