Nicodemus was an old prophet in The Secret of NIMH. He was the wise, mystical leader of the rats until Jenner killed him. Derek Jacobi did his voice who would later go on to play The Master from Doctor Who.
Nicodemus was always very kind and wise who was the leader of the rats of NIMH. Like the other rats, he was captured by a man and was injected with some sort of experiment, which gives him and the other rats human intelligence. After escaping NIMH, he became the prophet and leader of the rats. Even though he is the prophet, he was also somewhat a wizard judging by his items; the book, the amulet, and his crystal-ball-like machine.
Role in Film
He was the very first character to be seen in the film. He was writing down and narrating the events that happened that day (Jonathan Brisby's death) and reveals that it has been four (4) years since he and the other rats escaped from NIMH. He knew that they could not stay (in the rosebush) any longer. He kept an amulet belonging to Jonathon in a small chest, later to be given to Mrs. Brisby.
He watches over Mrs. Brisby with his crystal ball-like machine. He speaks to Jonathan about her safety. He watches her as she goes to see the Great Owl and when she came into the rats' home. He knew that Jenner could cause harm to her and the rats because of his thirst for power and he said, "When Jenner finds the amulet, then heaven help us".
He soon sees Mrs. Brisby in person. He first had her read the book about Jonathan. When Mrs. Brisby asks why her husband never told her about him and the rats, he tells her all about NIMH and Jonathan's heroism. He then gave her the amulet saying that Jonathan made it for her and tells her of its powers. He also tells her that Jonathan never told her about NIMH because the injections slowed their age process, which means that when Mrs. Brisby grows old, Jonathan would still be young.
While they were riding on the boats, he told Mrs. Brisby about the plan to move to Thorn Valley and start their own colony. When Mrs. Brisby volunteered to drug the farmer's cat, Dragon, he accepts the offer despite Justin's protest. He was next seen standing on a rock, watching the moving of the Brisby home. Unfortunately, he was unaware of Jenner's plan to kill him until it was too late. Jenner cut the ropes, causing the construction to break apart and crush him (Nicodemus) to death. He had sacrificed himself to save Brisby.
He is seen in the flashbacks in the beginning of the film. It is revealed that during his lifetime, he made a prophecy that Jonathan's youngest son, Timothy Brisby will