A Hentai System in the World of Danmachi - Chapter 9 - 8 - Battles inside the tower. Experience points.

In a world ruled by strength and chaos, a soul from modern Earth awakens in the frail body of a seven-year-old Sakazuki. Orphaned by pirates and left with nothing but a burning hatred, he refuses to remain weak. With knowledge from his past life and the power of the Magma Magma Fruit, he begins his ruthless ascent through the ranks of the Marines.But justice is not so simple. Corruption festers within the very institution meant to uphold order, and the line between protector and tyrant blurs with every battle. Undeterred, Sakazuki will forge his own path—one paved with fire and blood.From a vengeful child to the most feared force in the Marines, witness the rise of a man who will set the seas ablaze and redefine what it means to bring order to a chaotic world.

Within the Immortal Realm, there were nine thousand major realms, with three thousand at the top, three thousand in the middle, and three thousand at the bottom, along with countless minor realms.

In her previous life, she was a highly respected Heavenly Empress, but on the eve of her wedding, she was betrayed and died by self-immolation!