Nothing lasts forever. In no other realm is that truer than in the world of sports, in which a competitor's fortune can turn to torment in a matter of minutes.
The same applies in the world of MMA where literally seconds decide the outcome in the cage/ring. The fighters on this list know all too well how quickly things can change.
They had promising careers, but those dreams of becoming world champion (or leaving behind a lasting legacy) were cut short due to a number of reasons. For some of these fighters it was injuries, while others simply lost the desire to continue on in the sport.
There will of course be fighters whose premature departures wouldn't be considered unanimously tragic, given how subjective the term "tragic" itself is when describing an athlete fans either boo or cheer. But that doesn't mean this group of combatants wasn't meant for bigger and better days.