Kim Sunggyu young people aged 16 years have a brown hair and charming eyes emerald green Colored.

Kim prestigious family, the father, Kim Soohyun, is host to survive.

His mother was died when his younger brother was born, but despite this, he retains a vivid personality, confident, and energetic.

All of this starts when Sunggyu turns sixteen. At the ceremony to celebrate his reaching of the adult,

he was dragged into the abyss of the sin of existence. There he meets a young girl named Rin who turns out to be a chain.

Sunggyu made a contract with her in order to escape from the abyss. Upon returning to the real world, he finds out that 10 years have passed.

To find out what he sin meant, he began to work under Lee Sungyeol, Sharon and Jang Woohyun as part of Pandora.

When some of his memory remind him 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 he did not want to touch.

After experiencing this, Sunggyu 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, Sunggyu meets Kim Mingyu and in turn becomes his 'medium'.

Mingyu eventually speaks at Pandora's headquarters and the public hail Kim as a 'hero'.

Sunggyu, himself, thinks of Rin as his precious someone, calling her his "sun".

He believes that Rin is the reason that he can still smile.

Minggyu tells Sunggyu that he has the "right" or "prerequisite" over Rin's powers and that a seal won't restrain Rin's powers any longer,giving Sunggyu the ability to use B-Rabbit's power, even without Rin's permission or Woohyun's help.