I think that the three mugos are a god that were created from lee muhan, while he was just a human that deserved to go to the afterlife and find peace. But as we know, he couldn't have done that before because he was holding a grudge towards the luna village for so many years
I dont understand why the Human mugo or the very first mugo had to go to afterlife??? Isn't three mugos and him all the same person??