Master Chief

"There's John-117. He's also known as Master Chief. Can't believe this guy has got the United Nations Space Command under control during this great conflict."

--Su Ji-Hoon, A New Hope Awaits

Master Chief Petty Officer John-117, more commonly known as the Master Chief, is a SPARTAN-II commando of the UNSC Naval Special Warfare Command. He is the protagonist and main character in both the Halo trilogy and Reclaimer Saga. With over thirty years of active duty, he has become one of the most decorated war veterans in the United Nations Space Command, earning every known UNSC medal except the Prisoner of War Medallion.

In When the Cold Breeze Blows Away, he is also a partner to the Girl Union and the Sonic Alliance, including Su Ji-Hoon.