Once, while he was comitting a crime in a humble Korean suburb, Chang met a little man named Choi, who was outside a butchery. Chang found him to be very funny, and offered Choi to aid him in his crime business. Choi refused as he already had a job to sustain him. Still resistant, Chang tells Choi that it would be fun anyhow, and with his help, they won't ever get caught. Choi finally accepted his offer, as he was quite bored of his daily life, and wanted a bit of excitement...but they agreed that they shouldn't tell anything to Choi's wife!

So, began the evildoings of Chang and Choi, a duo feared among the banks and tiny shops. With their combined powers, it was unlikely to stop them! Chang and his impressie strength allowed them to break through barricades, allowing him and Choi to run away with the loot. Chang didn't only did this for the money, but he also found it very funny. He was also very happy to have Choi with him, since he found him to be a very good friend. However, Chang, not being so bright, wasn't so smart to think about everything, and he was once caught by the police, which had formed quite an impressive number around Chang and Choi. However, as promised, Chang made one last attempt to free Choi, and he helped him in his escape, while Chang was sent to prison, where he obviously, didn't stay for much time.

When Chang escaped, he quickly reunited with Choi and planned their next crime. They soon found a client in a passing woman, whom seemed to have a lot of booty on her. It was the time to attack! Suddenly, a white stream passed in front of their eyes. What was that? Then the duo was swept away. A man stood in front of them. With a challenging pose and a serious sight, the man introduced himself as the fighter of justice, Kim Kaphwan! Chang and Choi laughed at such a puny man, but they unexpectedly got thrashed by him in no time. Kim then picked them up and told them that he would take care that they would be men of good once again! Chang sighed and moaned...his life of crime was at a hault. Now he would know true punishment at the hands of Kim Kaphwan.

Chang, during the past years, has been obligated to train himself in the art of Tae Kwon Do, and fighting in the King of Fighters tournament. However, Chang never loses hopes that he will be free again and begin his crime life again, but when he always expresses his mind, he always gets caught by Kim and a subsequent beating. It seems Chang won't be a free man anytime sooner!

While enduring the harsh training with Kim, Chang was surprised by the arrival of a man that was once the training partner of Kim: Jhun Hoon. His bad- ass attitude made it seem that Chang would finally have someone aside him (besides Choi). However, it seems Jhun shares the same ideals as Kim, but marked with his own tone of violence and cruelty! It seems that the punishment for Chang would be never-ending! And it will soon get worst, as Chang is assigned to Kim at the end of the fifth King of Fighters tournament, in order to settle the personal difference between Kim and Jhun regarding which justice method is best.

After another hellish period of training with Kim for one eternal year, Chang comes to the brilliant resolution that, if he and Choi manage to defeat the NESTS cartel, they will be justified enough to be free! And so, Chang strangely fights with all his might in order to make a good impression on Kim's eyes, but he isn't so convinced by Jhun (who really doesn't impress himself too often). His hopes grow high as they near the final match in Southtown, but once they arrive at the crime-filled city, they are met with the inminent collision of the Zero Cannon shot! Chang and Choi do not manage to escape from damage's path, but they are saved in the nick of time by their own punishers: Kim and Jhun.

After waking up from unconsciousness, Chang realizes with shock that he has exchanged bodies with his friend Choi! Now, Chang has to deal with yet ANOTHER ordeal...having to live in an incredibly small body for his huge anger. That is, until they manage to find a solution from NESTS themselves.

The problem of the body exchange was quickly resolved thanks to Kim's creative plan: the two former convicts would bash their heads together repeatedly until their bodies switched again! Both partners-in-crime ended with a huge headache (but Chang was used to it, banging his head against his iron ball for so much time), but finally returned to their original bodies. Just in time, too, as the next King of Fighters tournament would begin soon, but things were looking pretty bleak as Jhun got wounded in a street accident, and was out of comission. Chang's joy didn't last long, as a substitute was quickly found for him. The new member was a young woman, no less! Her name was May Lee, and she was totally different from Kim and Jhun: aside from being greatly skilled in Tae Kwon Do (she hailed from the Tae Kwon Do dojo that Kim ran), she was quite a nice young lady, and acted generous towards Chang and Choi. It seemed like this year would go smoothly as never before!

The tournament once again staged the chance for Chang and Choi to show their so-called "improvement" as men of justice, and the destruction of NESTS actually did kind of did something for their image. The people of Korea celebrated their return, considering they were the ones who destroyed NESTS. But Chang felt happy for May Lee, who had finally made her dream come true: to fight for true justice. As Kim and Jhun quarrel about their claim for fame, Chang agrees with Choi in that the only true figure this year, was May Lee. Chang will fight for his dream for liberty as well!

Chang is a joyful man, always seeing the bright side of things, and laughing at them. However, his life with Kim has left him very sad, and though he thinks Kim is a boring man, there's nothing he can do to avoid it! Chang is also very reluctant to keeping his mouth shut, and when he always talks ill of Kim, it's always in the wrong moment, earning him and Choi a swift beating. Chang cherishes his friendship with Choi, and both pass most of the time planning their escape when they're not training.