Disguised as a Necro warrior, Riddick returns to Helion Prime on the Necro ship to rescue Kyra (Alexa Davalos) and kill the Lord Marshal. Meanwhile, Lord Vaako (Karl Urban) is named first among Commanders making him heir apparent to Lord Marshal. Vaako and his wife (Thandie Newton) scheme to kill Lord Marshal until Dame Vaako realizes that Riddick is still alive. She suggests that Vaako let Riddick attack Lord Marshal first in order to weaken him so that Vaako can strike the killing blow while he is down. As the Necro warriors assemble in the Necropolis for the 'day of days' celebration, Riddick makes a leap for Lord Marshal, who easily evades him. Instead of having Riddick instantly killed, Lord Marshall invites Riddick to join with the Necromongers and shows him that Kyra has already converted. As Kyra walks past him, Riddick asks her if she's 'with him', but Kyra does not reply. Riddick reacts by throwing a Furyan blade at Lord Marshall, which nicks him slightly, and they turn on each other. Using his Half Dead powers, Lord Marshal gains the upper hand. When he tries to take Riddick's soul, however, Riddick gets a rush of strength, and they go at it again. Just as Lord Marshal starts to gloat about his powers, Kyra spears him in the back. Lord Marshal retaliates by batting her across the room, impaling her on a spike. Realizing this is the best time to strike, Vaako grabs a Necro axe and makes his move but misses. Riddick picks up his Furyan knife and stabs Lord Marshal in the head, killing him. Tending to the mortally wounded Kyra, Riddick asks her once again if she is with him. 'I was always with you,' she says with her dying breath. In the final scene, Riddick collapses on the Necro throne, and the Necromongeers kneel before him. 'You keep what you kill,' Riddick reminds himself.