Month
What about his flavour text? In the final days you could edit his flavour and add stuff like before he became a ghost he was the most poweful (choose class) and he had a bunch of skills, give him some backstory too like he was the most talented person in the 9 realms and received the blessing of yggdrasil, so that when he got isekai'd he gain more skills too
I really Hope MC makes some Lord of the Rings NPC maybe even Ancalagon the Black the Size of that NPC would be enormous considering the dudes corpse Destroyed 3 entire Mountains. Or even Sauron, the Nazgul, even the dwarves and Elves maybe give Them all the Crafting Classes. And then some Human NPC maybe for Roleplaying.
I hope that in the last days of the game the MC pays the Devs to make a personalized world item for himself with a higher power even than one of the " 20 " . Like a heart that provides him with infinite mana and allows him to have no lvl limitations , capable of traveling to other realities or something like that. XD thanks for the chapter.