Chief R was held captive by Wild Jango in Central Tower when X first arrived in Giga City. After he was freed, he resumed command of Central Tower and instructed X personally on the fight against the Rebellion Forces.
Judging from his rank, Chief R was most likely an established member of the government sent by the Federation to Giga City, perhaps something like a viceroy or assistant to thereof. Chief R possesses a very calm, reserved personality, but is also decisive and prudent, evident when he instructs X to rescue Nana and the captives of Tianna Camp as first order of business after control over Central Tower is re-established. He also appears to be a strategist and due to his lifetime career at Giga City, he is very knowledgeable of the surrounding areas of the island and its residents.
Tragically, however, he was killed in an ambush set up by Colonel Redips. As Chief R was signaling a military airship (which was sent by Redips under the pretense of transporting the Maverick Hunters back to base) to land, the aircraft instead opens its underbelly to reveal cannons instead of landing gear, fires on him.