One of the greatest of all time, Demetrious Johnson , is now a retired mixed martial artist. During the ONE 168 broadcast, Johnson (25-4-1) stepped into the cage to announce his retirement, ending a legendary professional MMA career that began in 2009. The former UFC flyweight champion has decided to call it a career, and is taking the ONE Championship flyweight (135 pounds) title with him. While quipping jokes to help fight through tears, Johnson thanked his team and his family for being by his side throughout his journey in combat sports over the years. “Like I said last time, when I came here to Denver, Colorado, I told you guys that was potentially my last fight, and I was not lying,” Johnson said during his speech. “I am done.