Oz Vessalius is the fifteen-year-old protagonist of the story with blond hair and green eyes. He is from the prestigious Vessalius family, whose father, Zai, is the reigning lord. His mother was killed by the Nightray family, but despite this, he retains a bright, optimistic, and energetic personality. The story of Pandora Hearts starts when Oz turns fifteen. During the ceremony to celebrate this reaching of adulthood, he was dragged into the Abyss for the 'sin of his existence'. There he meets a young girl named Alice who turns out to be a Chain, a monster that was born in the Abyss. Oz makes a contract with her in order for both of them to escape the Abyss. Upon returning to the real world, he finds out that 10 years have passed. In order to find out what his sin meant, he began to work under Break as part of Pandora. During this, it is shown that when he was young, he worked hard to gain praise and recognition from his father. However, he had discovered that his father hated him to the point of not wanting to touch him. After experiencing this, Oz began to think that there is no guaranteed thing in the world. He thought of himself as weak and, in order to protect people, he should at least remain an obedient child and let harm come his way. After traveling into the Cheshire Cat's lair, Oz meets Jack Vessalius and in turn becomes his 'medium'. Jack eventually speaks at Pandora's headquarters and the public hail Oz as a 'hero'. Oz finds that he can swap control of his body with Jack if he calls hard enough and may sometimes even see snippets of Jack's memories. According to himself he is quite skilled with the sword, particularly in self-defense. However, he has very little real experience in fighting. Oz likes cute, younger girls and flirts with them frequently. He once wished to marry Sharon when they first met. Oz, himself, thinks of Alice as his precious someone, calling her his "sun". He believes that Alice is the reason that he can still smile.