Reincarnated in my own Novel as Final Boss.

My grammar is not too good since my first language is not English.
synopsis:-
A man died on earth and reincarnated as the final boss of his novel.
But the problem is the final boss once was a kind man but fell into darkness due to some incidents in his life.
To know how?? , why ??.

Why you should read this novel?
1.Cause we have a milf elf, fox girl, dwarf girl, cold iceberg type girl, tsundere, yandere girl waiting for you, so you can save them from this cruel world.
2. No mindless smut, a pure romance novel and obviously some R18 stuff, an action novel, and a fast paced novel.

tags:- harem, weaktostrong, netori, Villain.
no ntr
keep up with the story, I will try to improve my grammar.