Radok Ranzaad, sometimes romanized as Radok Lanzard, is a supporting character in the anime series Slayers Revolution and Slayers Evolution-R. In public life he is a wealthy and successful merchant of tall build and dark hair, but his private identity is that of Zuuma, a highly skilled and widely feared assassin whose reputation is so well known that even the princess Amelia recognizes his name. He is regarded as an assassin among assassins, and as a fighter he relies primarily on physical skill, insisting on killing his targets with his own hands and using magic only as a supplementary tool.

In this anime version of his story, Radok is defined by grief. He loses his wife, and the anime depicts the distressing process of her body decaying into a corpse along with Radok's shock and despair at the sight. This trauma erases his professional detachment, and the story presents him as an assassin who has abandoned any sense of professional pride and continues to target Lina Inverse out of a purely personal grudge.

His scheme is built on deception. After an attempt on Lina ends in his defeat and the loss of both arms, he is restored by fusing with a mazoku, a demon, which grants him new arms and greater power. He then returns to the identity of Radok and stages the situation so that a death threat appears to have been sent to him by Zuuma; acting on that supposed threat, he hires Lina and her companions as his bodyguards. In truth, the hiring is a means of drawing Lina into his reach so that he can settle the conflict personally. This dual role makes him an unusual antagonist, because he is simultaneously the employer, the supposed victim, and the would-be killer, and the story's conflict turns on the revelation that these roles belong to one man.

Radok's relationship with his son Abel Ranzaad shows another side of his plan. Abel knows what his father intends to do, and instead of supporting him, he deliberately behaves in a surly and condescending manner toward Lina in an effort to drive her away and spare her life. The tension between father and son suggests that Radok's obsession with revenge has damaged his family and that Abel does not share his father's desire for blood. Over the course of the arc, Radok develops from a composed and respectable public figure into a desperate, grief-stricken avenger who sacrifices his reputation, his relationship with his son, and even his own body in the pursuit of a final confrontation with Lina.