Cornelius

Doctor Cornelius, the important mentor, advisor and teacher of King Caspian X, was a man of half-dwarfish, half-human blood and one of the few people in the Telmarine-ruled society of Narnia under King Miraz's rule that knew of the old ways and stories.

In Prince Caspian
When Doctor Cornelius is first introduced, he is to be the tutor of Prince Caspian X and to teach him the basics of art, science, history, mathematics and music. He eventually learns of Caspian's former nurse, who was like Cornelius, a half-dwarf, and learned that Caspian was interested and favorable of the past of Narnia, which he had been taught to be fairy-tales from his tyrannical uncle and adoptive father, King Miraz. Doctor Cornelius tells Caspian of Narnia's true past and that Miraz was a usurper who killed his father, then told him of the fact a prince was born to Miraz and Cornelius helped Caspian escape. Doctor Cornelius remeets Caspian to help him organize a army and advise him in tactics, telling him of two great places where a miracle may occur, and from which Caspian sent two of his men. In the end, Caspian makes Cornelius his Lord Chancellor.