During the war against the CIS Emperor Palpatine Aware of some members of the confederacy's desire to end the life of Padme Amidala, and though that was to be her penultimate the always cunning Sith lord did not want that to happen before it's time if it could be at all helped. And so, while the war raged on in secret was able to collect some of her DNA and through a project known as "Endeavor" commissioned a secret battalion of clone troopers with her DNA. A battalion that had become known as the '066ers'. A battalion that was always under the direct control of Palpatine himself, no Jedi was ever in command of this group as it was labeled 'experimental'. Rumors about a group of Female Clone troopers seemed to be but whispers and wildly discredited among political circles, and even by the Kaminoans, as not a single female clone was actually produced on Komino, their project took place off world on one of it's Gas Giant planets nearby.
The battles they waged were ultimately secret, an devices built into their code would render their bodies unrecognizable once killed in order to protect Endeavors integrity. As warfighters they were incredibly effective, and generally only worked in small skirmish engagements more as a scalpel force instead of the blunt tool that the Jango clones were wildly utilized. As that was the case they usually found strong bonds among Sisters, and generally found themselves superior to their male brothers. Though would never say it to their faces if they ever did cross paths.
Ultimately, their job was to be ready to take the reigns as Senator Amidala should her ultimate demise be realized. The woman had a surprising knack for getting into trouble, Sidious realized this and so created the Endeavor clones should tis scenario come to pass, one of them would simply take the reigns and continue to live as though she had never died. As such, during their training they would have to prove their worth by going through rigorous training as a senator, as well as combat training and simulation. One of the more difficult scenarios being the Arena challenge. Where the Clones are faced with the same life or death situation Padme had been subjected to by the Geonosians. Failure was not an option during this critical examination, and more often than not they would be slain by the creatures sent in to fight them.