Pan is said to have died when people ceased to worship nature and the wild. People stopped worshiping the nature spirits, the Naiads, the nymphs etc.
In fact it is almost widely accepted that the death of Pan marked the advent of theology and Christianity. It is said that Christ was born as soon as Pan died ( It is not clear whether Christ was born after Pan died or Pan died after Christ was born ). People stopped worshiping the nature and started worshiping Christ. As a result nature went un-acknowledged and Pan “died”.
The other god is Asclepius; God of Medicine, Healing, and Rejuvenation.
His myth is very different. Asclepius is said to have been killed by Zeus as Asclepius had brought back Hippolytus back from the dead in exchange for gold. This angers Hades who asks Zeus to **** him. Zeus kills him with his thunderbolt.
It is said that later Zeus brings him back and orders him not to bring back anyone from the dead without his permission