They'll do their job well, I guarantee that.
—Jango Fett
The Special Elite Clone Commandos, also called the S.E.C.C., were special clone commandos from the Clone Wars. They were commandos that had been sent out in war before Obi-Wan Kenobi first found the clones on Kamino. They had already seen war and had developed their own personalities. They used to work in pairs of two, but sometimes worked alone or in squads. After the Empire was created, Palpatine never knew about the elite commandos, so they continued to work together with the hiding Jedi.