Quinton Jackson wears a steel bicycle chain around his neck, has a tattoo of a black panther on his enormous bicep, and has a tendency to howl like a wolf. He is also born-again, the loving father of four children—and known for delivering the hardest blow in the history of professional sports. Now, in attempting to defend his Ultimate Fighting Championship title, he is also trying to hold onto his sanity. An intimate portrait of a mixed martial artist—and of the growing American fixation with the warriors who earn their living beating each other bloody.

A profile of Shad Smith, the only openly gay MMA fighter in the world.

Boxings decline, and at least for now its eclipse by mixed martial arts, represents more than merely the sunset of a sport that was once extraordinarily popular and is no longer. Other diversions have come and gone through history horse racing has similarly slipped out of mainstream culture, with only those who cling to a minority passion lamenting the passing. Six-day bicycle races were once front-page news; things change.