Han's specialty was his compression of Qi. Due to him being a middle-stage warrior, he had a large pool of Qi, but even more so, he was able to compress it extremely far down to allow it to explode at a point, making it appear stronger.
It was a technique that he had learned to survive, to complete the tasks set by his father.
A technique formed from having to complete impossible missions. It was because of this that Han could often defeat those considered the same rank as him.
Even if there were those that had better techniques, he would often come out as the winner.
When Han received the special item from one of his battles—the flute—his strength had increased exponentially. He could input his pure condensed Qi into the flute, creating sound.
The sound would act as a wave and was quite close to what people would consider projectile Qi. Through the sounds, Han was able to attack his opponents.