Hall of Valor System: Just a Mortal, Want to Win Against the Gods?

I have a Book of Heroes. When I prayed to the gods, the sword gods, fire gods, martial gods, and demon gods in the Hall of Valor all responded to me! The Book of Heroic Spirits is also a "job change book". After all, you have to be a pure white priest to use it to change jobs. One week, that is, in the previous life, Chamberlain missed it. He became an old man in this fantasy world. When he was about to die, a big explosion occurred in the whole world! Now in the second episode, he wants to find out the cause of the explosion and save the world...! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.