Life throws all of us obstacles. Everyone meets barriers. Nobody is immune from setbacks. It’s how we confront and navigate past the curve balls life throws that moulds character and ultimately defines who we really are.

Do you crumble or rise to the challenge? Do you shrink down and become the victim? Or do you stand tall and walk through adversity like a warrior?

And what do you do if everything just goes to shit?

You are hard pressed to find a man who has met so much adversity with such a grounded sense of purpose and honest willingness to share about it as Mark Miller.

Meet Fightshark. Just make sure you check your grousing at the door.

Born with both Type-1 Diabetes and a congenital heart defect (CHD), Mark was reared by the back hand of an alcoholic abusive father. A World War II vet and notable professional athlete who played in the very fist NBA game ever, “Moose” Miller was a domineering force of nature who experienced the world as a dark, unfair and often violent place – and made sure he prepared his son accordingly.

To escape the emotional and physical violence that greeted him at home, Mark immersed himself in the world of sports at a very young age. Thrown into a boxing gym at age 6, he quickly adapted, eventually mastering every sport imaginable by the time he finished high school. During his free time he worked in the Pittsburgh Steelers locker room (from age six through high school), grabbing towels, taking grief and learning about sport and life from the hand of legends like Lynn Swann, Mel Blount, Jack Ham and Mean Joe Greene while also working on his pitching with guys like Barry Bonds. All champions that in some sense served surrogate dad duty for this evolving teen.

By the time he was 18, Mark was poised to go professional as a major league pitcher. But Mark had other plans – he wanted to become a professional kickboxer.

By 2007, Mark was a rising star in this emerging sport until a routine physical uncovered a serious cardiac condition that required open-heart surgery to replace his aortic valve.

The crisis helped to temporarily reunite his fractured family. But everybody thought Mark's fighting days were over. Once again, Mark had other plans — the surgery just made him more determined than ever to return to the kickboxing ring. Astounded by the rapid rate at which Mark's heart healed, his doctors gave him the green light to resume training. Everything in Mark's life seemed to be getting back on track.

But 2008 had little respect for Mark's plans.

Over the course of that year, Mark lost both his parents and his drug addict brother to an overdose. A confluence of events that led Mark to lose himself in drugs and alcohol, culminating in a boozy accident that hurled his already fractured and fragile body through a car windshield and onto hard unforgiving Austin, Texas pavement.

Eventually, Mark found the wherewithal to get and stay sober. Renewed, he set his sights once again on his kickboxing comeback. Despite being labeled damaged goods, in 2011 Mark returned to the ring in Moscow and shocked the fight world when he took out one of the world’s best with a knockout in just 8 seconds.

To this day, Fightshark is the first and only combat sport athlete to return to competition after undergoing open heart surgery.

Fast forward to 2013. Just prior to his fight debut in storied Madison Square Garden, Mark contracted pneumonia, which set in motion a devastating domino effect of health cataclysms that have left him with chronic kidney failure, blindness in one eye, and the need for not one but three organ transplants: heart, pancreas and kidney.

Mark is currently fighting for his life. Literally.