Ascension of Lightning God (Dropped)

(The first part of the story will be slow and have long prolonged chapters. Read at your own taste) This is a story of both the ascension of Lightning God and the love story of two people. MC is loyal to his lover and there will be no harem, though Mc will be overpowered. The story takes place in supposed hollow earth, Agartha. This is my fantasy. Work of imagination. Every content and words may or may not true as this is just a fanfic. Please enjoy it. The first world is 'Demon slayer'.