There are many characters that have appeared in the Redwall series, including the books and television series written by Nick Danby.
Asmodeus Poisonteeth was a giant male adder who lived in an old sandstone quarry north-east of Redwall Abbey. He was also called "Giant Ice Eyes" by the shrews due to his possession of hypnotic powers. He had been known to hiss his name, and was unwittingly found by two of Cluny the Scourge's officers while dragging off another of his captain's corpses. For several years he had possessed the Sword of Martin, which he took from the sparrow King Bull Sparra. The mouse Matthias ventured into the adder's nest in search of Martin's sword. The serpent was found sleeping in the cave in which Asmodeus held the legendary sword. Matthias retrieved the sword but Log-a-log, the leader of the shrews, ran in and shouted hysterically on spotting the corpse of his shrew comrade Guosim, and the snake came awake. With the sword he had taken, the mouse warrior quickly dug a hole out of the cave, and he was pulled out of the den by Log-a-log. The snake gave chase, and was stuck in the small hole. He tried to hypnotize the two creatures but a vision of Martin the Warrior came in Matthias's thoughts and he broke out of the snake's evil look. There, the reptile was destroyed, having his head cut off by the great sword's unbreakable edge.
In the book Outcast of Redwall, it is shown that the quarry was filled with adders before Asmodeus lived there, perhaps his ancestors. It is also revealed in the book Triss that Brockhall, abandoned after the construction of Redwall, has become the residence of adders, possibly descendants of Asmodeus.
In the book, Asmodeus's role is fairly neutral—he is not good, he is not evil: he's just hungry and greedy, and his stealing of Martin's sword seems almost magpie-like, or perhaps similar to dragons taking hordes of treasure.
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