Jeong-woo Cha is Yeon-woo Cha's younger twin brother. He was one of the strongest and the most famous high-ranker in the Tower before he was betrayed by his teammates leading to the events of the main story.

Jeong-woo was described by Yeon-woo as being a weak and introverted person who liked books, movies, and had a talent of not needing much work to succeed in most things. Furthermore, he also greatly valued his family, even leaving home in order to find a cure for his mother.

(Source: Second Life Ranking wiki)

Yeonwoo’s brother disappeared years ago, and he’s devastated to learn of his death. As he copes with his loss, he’s given a pocket watch and learns there’s more to his brother’s death: he was betrayed while competing in the Tower of the Sun God. Now it’s Yeonwoo’s turn to use the knowledge his brother left behind. Can Yeonwoo (call sign: Cain) navigate that world and gain enough power and experience to reach the top of the tower, defeating his brother’s enemies and all those who stand in his way?
<br><br>
(Source: Tapas)

Jeong-Woo Cha