In general, it is almost impossible for humans to be satisfied with their problems and have the same personality from beginning to end. Personalities will develop over time, as do the characters in literary works. This study aimed to find Rayne's personality, who was the main character in Julie Pike's novel The Last Spell Breather (2019), using M. J. Murphy's characteristic theory to analyze Rayne's characterization and find Rayne's personality by utilizing personality theory and personality development theory of Elizabeth Hurlock. In this study, a qualitative descriptive method was used where dialogue and narrative from the novel The Last Spell Breather as the source of data. The results of this study found that Rayne's original personality before Rayne experienced personality development was Kind, unconfident of her ability, lack of physical self-control, beliefs she could trust anyone, and honest. After being driven by strong motivation, changes by significant people, changes in roles, and changes in self-concept developed Rayne's character into adaptability, courage, self-confidence, and a responsible personality. Some characteristics of development were better versus worse, where in this study it was found that changes in Rayne's personality were better as it was useful for Rayne. Then, quantitative change is where a personality is strengthened by an existing personality, while qualitative change is where a personality is changed or replaced by a new personality. Then, there were rapid or gradual changes in personality development experienced by Rayne. In the results of this study, the changes experienced by Rayne occur gradually. This study concluded that Rayne, who initially doubted her role as a spell breather, finally accepted herself and became more confident in her abilities.