Nadaz is a villain in Redwall. He is a servant of Malkariss and leader of the Blackrobe Rats. He receives messages from Malkariss and gives them to his followers, hence his title "Voice of the Host."
When Slagar decides to make demands to Malkariss, he angers Nadaz and he has his minions take him away.
In the books, he is the one who warns Malkariss that his kingdom was being invaded. In both versions, he plays a drum to alert the Blackrobe Rats to prepare for battle.
When he realized that Malkarris would lose to the heroes (Malkariss had in fact died when the slaves decided to revolt against him), he decides to hide in Malkariss's statue until the battle was over, hoping to rule whatever was left of the kingdom afterwards, in addition to rebuilding it.
However, his plan would fail miserably as Matthias and Orlando the Axe decided to destroy the statue after realizing that it represents the misery of the slaves, accidentally killing Nadaz in the process.
He wielded a staff with a skull on it.
He only wears purple in the book