Jhun and Kim trained in the same martial art, but each developed their own technique. Besides being different in their style, they also had different justice ideals. While Kim trusted people and aided them when in need, Jhun supported the idea of an iron fist justice, and strict discipline. This is what made the two masters rivals in their own game. After completing their training, each one goes their own way, to see who was finally right.

After years of kicking the living hell out of criminals worldwide, Jhun decides that it is time to go back to Kim and show him the results of his travels. Upon arriving at Kim's dojo, he watches two particulary funny figures training in the backyard: one being a small midget with a hat and iron claws, the other being a large giant wielding an iron ball. Jhun recognizes them as the two famed Korean criminals, Choi Bounge and Chang Koehan. After Kim greets him, Jhun wants to know what those two are doing in his dojo. Kim tells Jhun that he has accepted his fate to train those two and completly reform them. Jhun laughs and considers Kim's methods obsolete. He shall join him so he can teach him how it is really done!

Things couldn't get worse for Chang and Choi. Besides having to support a good-natured psycho, they had to get the worst out of a psycho by nature. While Jhun and Kim can't fix their differences in training, Kim proposes Jhun to enter the King of Fighters tournament with him, and then they would see who's who. Jhun agreeds, and makes a promising entrance in the battle arena. However, after the battles end, both still argue about the same tune. Only one thing is left to do: each one will take one of the convicts and train them their own way. Jhun chooses Choi, and vows to deliver him completly reformed by next year. Only hard discipline can take you anywhere!

Jhun begins his ferocious training on the poor Choi. His iron-hand discipline is determined to beat the evil right out of Choi! More than attempting to reform Choi, however, Jhun trains himself a lot in order to show Kim who the real master of Tae Kwon Do is, and to show him his wrong ideals of justice...and assisting to the concerts of Athena and her band (which Choi doesn't really understand the relation with training). Jhun considers himself to be worthy enough to be the new Korean justice fighter, so when he reencounters with Kim after a year, Jhun considers it to be a final test. The goal: To see who can destroy NESTS with their beliefs. Jhun will concentrate all his fury in doing just that!

After arriving at Southtown, the location of the final battle, Jhun burns in anticipation of destroying NESTS once and for all. His plans fall short, though, as he finds himself in the middle of the destruction of Southtown by the Zero Cannon! Jhun manages to leap out of the path of destruction, but he sees how Chang and Choi don't. With drawbacks, Jhun, along with Kim, saves the two ex-criminals from sure death. As they wake up, it is revealed that Chang and Choi have now changed bodies! Jhun considers it to be quite a bad omen, but no matter who has to pay, he will get things even sooner ot later.

The next King of Fighters tournament looks pretty promising for Jhun, as a new year comes around. He has trained for a whole year to participate once again, and with new enthusiasm after Kim managed to brew up an idea to exchange Chang and Choi's bodies back (due to a quite rude head-butting therapy). But after hearing news of a new Athena Asamiya concert in Korea, Jhun wasted no time in going to the event. He was running a little late, so he rushed down the traffic-filled streets. As he ran down the street, a glimpse of a young woman who looked like Athena crossed his eye. Confused by the vision, Jhun tried to call the attention of the Athena lookalike. But he never paid attention to the car he was just about to run into, and hit the vehicle violently. Jhun ended up in the hospital with a broken leg, and so was his dreams about entering the next King of Fighters tournament (although it was said that the car was even in a worst condition than Jhun himself!).

While at the hospital, Kim showed Jhun who would be his replacement for the King of Fighters tournament: a young Tae Kwon Do student called May Lee. She was quite enthusiastic, and Jhun never did complain (although he was being ignored when he tried to give out his opinion). Jhun was forced by medical advice to watch the tournament from the sidelines. He lost contact with Kim and the others when they were about to board a blimp for the finals. Soon after, news of the fall of NESTS' space station and their demise reached Jhun and all the other Koreans. The people thought it was Kim and the others who finally punished NESTS for their sins, but Jhun also wants a bit of credit in the whole celebration. As soon as Kim arrives in the welcoming party, Jhun and him get involved in a rowdy bash to define who truly deserved the credit. It looks like they won't be agreeing on anything for quite some time!

Aside from being so sarcastic and short-tempered, Jhun's ideals are noble at heart, and only desires to fight for justice and thwart evil. His rants normally end in violence, but he is usually a calm man if not messed with. He passes a lot of time by himself, contemplating on life more often than not. He is also a big fan of Athena's music career, and he doesn't like to show his weakness towards her in front of Kim in the KOF tournament (in which Athena has always been a regular participant). He respects Kim as a person and fighter, but totally disagrees in his philosophy!