In the films, Vin Diesel plays the eponymous Riddick, who is a mercenary, a warrior, and overall super-fighter. Riddick has surgically-altered eyes, allowing him to see clearly in the dark, and, like most action heroes, can wipe out an army of foes single-handedly.
But all the work needed to go into a film like this is a tall order. On the red carpet premiere of the film, Diesel talked to ET about the physicality of a movie like Riddick.
"The physicality is intense. Most of the characters I play call for physicality," Diesel said, referring to the many action roles he's played in the past, including XXX and the Fast and Furious franchise.
Although, according to Diesel, it wasn't the physical training that was the toughest part, it was getting into the his character's headspace.
"The kind of reclusive nature of the character was probably the most taxing. So it was very good for me to, three months after that, go back to the family setting, like Fast 6. Because that Riddick character can be a very lonely character at times."