Who is in charge of the judge's pen?

According to ancient myths and legends in China, the judge's pen is regarded as the judge in charge of the underworld. The judge is in charge of life and death in the underworld. Their duty is to judge people's life and death, punish bad people and reward good people. In Mr. Jin Yong's martial arts novels, there is also a weapon called the judge's pen, but it is not clearly pointed out which character is in charge. The person in charge of the judge's pen may be different because of the different story background and cultural tradition.