In the work " Dafeng Nightwatchman," the supervisor's identity was a part of the Heavenly Dao. He was the embodiment of the Heavenly Dao's will, so the disappearance of the supervisor meant the return of the Heavenly Dao's will. The death of the supervisor did not explicitly mention that there would be a new supervisor to replace him, but from the perspective of the Will of the Great Path, the role of the supervisor might be continued by other manifestations of the Will of the Great Path. Under the guidance of the Will of the Heavenly Axiom, new characters or powers might appear to maintain or adjust the operation of the Heavenly Axiom. However, the exact identity of the new supervisor would depend on the subsequent development of the work.
While waiting for the TV series, you can also click on the link below to read the classic original work of "Dafeng Nightwatchman"!
The easiest way could be to subscribe to comic book subscription services. They'll deliver the TWD comics to your doorstep regularly. Another option is to check out conventions or comic fairs where you might find special editions or rare copies.