The jade emperor is the god in charge of the weather. He can control the changes in the sky, predict the weather and natural phenomena, and protect world peace. He didn't directly participate in the story of Jingjiu, but his existence had an important influence on the development of the whole story.
Jingjiu was a commoner in Shang Dynasty. An accidental opportunity to become the owner of Aoki brand, through which Aoki brand became a fairy. Jingjiu is a very important role in the whole story. He experienced many setbacks and difficulties and eventually became the patron saint of Shang Dynasty.
Although there is no direct relationship between the Jade Emperor and Jing Ke, they are both important roles in the Romance of the Gods, which plays an important role in the development of the whole story.