Teran
Teran is the central character in The Black Cauldron by Lloyd Alexande. Teran is portrayed as an intelligent young man determined to do good for his society. Teran works as an assistant pig keeper on the farm, where he does his work excellently. Teran is a close friend of Gwydion, the Crown Prince of Prydain.
When Teran learns that Gwydion is planning to steal and destroy the Black Cauldron, Teran is interested and offers to assist in accomplishing the mission. Arawn, an evil sorcerer, uses the Black Cauldron to create immortal soldiers to fight his enemies. Teran joins forces with his friends to steal the Black Cauldron. However, the assignment is risky because the Black Cauldron is under the custody of the most dangerous individual. Teran's sacrifice and determination enable him to destroy the Black Cauldron.
Gwydion
Gwydion is the Crown Prince of Prydain, determined to bring peace to the land of Annuvin, which the evil sorcerer, Arawn, has invaded. Arawn uses the Black Cauldron to create immortal soldiers who create havoc in the kingdom. Gwydion is a strategist and excellent planner. With the help of his close friends, Gwydion's army manages to defeat Arawn and King Morgan, who try to be obstacles in destroying the Black Cauldron.
Arawn
Arawn is the evil sorcerer who owns the Black Cauldron sword he uses to create a deathless army that terrorizes the neighboring kingdom. Arawn controls a large group of huntsmen who help him to attack enemies whenever his territory is invaded. For instance, the huntsmen try to defeat Teran and his companions, who steal the Black Cauldron Sword. In the end, Arawn is defeated, and the Black Cauldron is destroyed.
Ellidyr
Ellidyr is a close friend of Teran, who joins him in the search for the Black Cauldron. Ellidyr is a selfish and untrustworthy man who pretends to be a genuine friend. When Ellidyr and the other friends are set on a journey to steal the Black Cauldron, he plots to kill his friends after they find it. Ellidyr wants to be famous and honored after emerging as the heroic figure who brings the Black Cauldron. After Teran and his friends find the Black Cauldron, Ellidyr suddenly changes and threatens to kill everyone if they do not agree that he will deliver it to the Crown Prince. Teran unwillingly agrees, but he discovers that Ellidyr is a bad person.
Eilonwy
Eilonwy is a close friend of Teran, and she works as a scullery maid on the pigs' farm. Eilonwy is a curious woman who wants to be involved in every mission Teran undertakes. After realizing she is not part of the group selected to work with Gwydion, she feels isolated. However, she decides to join Teran because she does not want anything bad to happen to him.
King Morgant
King Morgant is an opportunistic individual who wants to take advantage of Teran's efforts to possess the Black Cauldron. King Morgant is power-hungry and wants to do everything possible to get the Black Cauldron to make immortal soldiers defeat his enemies. Fortunately, Gwydion discovers King Morgant's mission, and he strategically positions his army and defeats him. After defeating King Morgant, Gwydion's men, with the help of Teran, destroy the Black Cauldron.