Conor McGregor is the biggest name in mixed martial arts, and he’s well aware of the dangers that his sport present. Preparing for his highly anticipated rematch with Nate Diaz at UFC 202, McGregor recently discussed his time as an MMA fighter, including his most troubling experience of the past year.

McGregor was cageside in Dublin on April 9 as MMA fighter Charlie Ward won by third-round TKO over Joao Carvalho at an event for Total Extreme Fighting. Two days later, Carvalho was dead because of the beating he took from Ward, who is a teammate of McGregor.

“How do I feel? How would you feel?” McGregor asked in an interview with Men’s Health Magazine.

“It's f--ked up. I wasn't just watching that fight. I helped train a guy to kill someone, and then someone wound up dying.

“This is a f--king dangerous game. People call it a sport, but it's fighting. I'm just making sure it ain't me. And that's f--ked up.”

Shortly after the fight, McGregor said he felt it could have been stopped a little earlier, saying “these referees need to be on the ball a little bit.” Carvalho was rushed to the hospital with head trauma 20 minutes after the fight ended.

Up until his last fight, McGregor had sustained very little punishment during his time in UFC. The featherweight champ was 7-0 in UFC, winning with four first-round stoppages and two second-round TKO’s. At UFC 196 in March, he was forced to submit to a rear-naked choke by Diaz in the second round.

In the interview, McGregor also discussed his upcoming bout and what he thinks makes him a unique fighter.

“People are so caught in a routine, doing the same things over and over,” McGregor said. “I want to be an expert in different fighting styles, new training methods, new ways of thinking.”

McGregor defeated Jose Aldo at UFC 194 in December, needing just 13 seconds to win the UFC featherweight championship. After his fight for the UFC lightweight title was canceled because of an injury to then-champion Rafael dos Anjos, Diaz became McGregor’s opponent on short notice. The 145-pound champ moved up two weight classes to face Diaz at 170 pounds.

After McGregor fights Diaz on Aug. 20, he’s expected to have a rematch with Aldo, putting his featherweight title on the line for the first time.