|~ Emperor Palpatine to his Royal Guards|
The Royal Guards were once guards to the chancellor, the leader of the Republic. Palpatine later became the chancellor and replaced the Senate guards with the Royal ones. Not only the Royal Guards guard Palpatine, but entrust the secret that he is a Sith.
When Palpatine issued Order 66, the guards revealed their allegiance and protect their master. They were knocked out by Yoda before he dueled the Emperor. The Emperor won the duel and Yoda was forced to retreat.