Clones were identical genetic replicas of a living creature. The replica could either be made identical or modified purposefully. For example, growth and aging could be accelerated rapidly. The genetic structure of a clone could also be altered to make it more obedient than the original host.
The Assassin League was set up by Sith Lords Darth Statler and Darth Daniel to clone Noah Tolmach as an army for Daniel's usage to hunt down the remaining Jedi in the New Order. They were human clones, and named "Assassin troopers."