De acordo com a Wiki para o Riddick :
For 5 years Riddick has been neglecting the Necromongers as Lord Marshal and has yet to take the sacred oath or lead them to the Underverse. Several assassins try to take him out by orders of Necromongers commanders, but all of them fail. Seeing that he has let his animal side slip past, he orders Commander Vaako to take him to his home planet. When Riddick arrives on a planet he finds out it is Not-Furya, and the Necromongers betray him trying to kill him...
Então, parece que, apesar de ser o líder dos necromongers, ele estava muito inativo no papel e eles se cansaram dele.
Isso é o que o diretor, David Twohy, estava almejando como declarado em esta entrevista :
The first sequence is about 10 to 15 minutes of him alone on this planet, with no dialogue and just minimal voiceover. And then he goes into a... hibernation. Everything on this planet has tooth and claw. Everything is trying to kill him. So he basically entombs himself, to keep the predators away from him.
And as he falls asleep in his tomb, we flash back to the Necromonger world. We get the sense that while it's great to be King, you have to deal with the assassins outside your room. Sometimes the assassins in your bed, and all the betrayals that take place there. With our limited resources, I was able to do I think a pretty good [job] of that in the movie.