CC-3023, otherwise known as Royal (shortened to Roy), was a clone commander from Chandor Prime. He was based on an unknown Mandalorian clone template that was employed by the cloners on Chandor. He served in the 3rd Army, usually under Jedi Council member Mason Quarrell. He was a co-commander of the 146th Attack Battalion and the 11th Sky Corps. He was nicknamed Royal because he served under the Prince of Sicemon, Quarrell. Troops from different armies would call him "Royal" because he was in charge of protecting the highest profile and most important individuals of the Republic, collectively known by the code word "Royals".
Due to his service under Quarrell, he developed a personality that put the mission first and placed the objective above everything, including the health of his own troops. His somewhat cold demeanor put him at odds with some of his subordinates, while others praised him for his ability to go above his emotions to get the job done. His attitude was partially borne out of his tutelage with Mason, but also because he had extreme confidence in his men, to the point that he didn't worry about them on supposed "suicide missions" and volunteered them for the most difficult missions in the war. CC-2223 was particularly fond of Royal.
Behind the scenes
The Star Wars clone trooper legion, the 501st Legion, was the basis for Royal's armored appearance.