I Was Reincarnated as a Childhood Friend of the Last Boss Who Has Fallen Into the Darkness

I, Arx Fort, is a reincarnated person. Therefore, I knew that this world was the world of “Celestia Kingdom,” a popular otome game in my former world. At first, I thought I was a nameless mob, but it turns out that I am actually a childhood friend of the most fearsome last boss If the knowledge from my previous life is correct, won’t she fall into the darkness upon my death? I managed to become the strongest and avoid a bad ending. But something was wrong with her…. “Hey, why don’t you look at me…?”