Cuy'val Dar

Cuy'val Dar is mando'a for "Those Who No Longer exist."

The Cuy'val Dar
This title was given to the 100 training sergeants who Jango Fett recruited to run the clone commando training programme.They had to disappear; they couldn't tell anyone they were on Kamino, and because they didn't know when the army was going to be activated, they had no idea how long they'd have to remain there. Those who had families - and many of them weren't stable family folk, of course - just left them. As far as everyone else was concerned, they were dead or MIA.

Speculation
In her blog, Karen Traviss wrote: "they either needed the fee very badly, or they were insanely loyal to Jango, or they wanted to disappear for reasons best known to themselves...and so on."