Tensei Shitara Slime Datta Ken (WN) - Chapter 399

The eldest daughter of the Li family is beautiful and sassy, ​​she took space materials to flee famine, and after going through many difficulties in war, disease and epidemic, she united with her family to regain the glory and harvested a beautiful boy.

- Description from novelbuddy

“How long has it been?”10,000,000 Years, a period of time which he dwelled in the endless abyss as a captive of war.After his fall, he lost everything to the hands of those who stand above the heavens.The twelve gods of the constellations, the Primal Zodiacs!Creatures who descended down from the absolute light to consume all.He fought against them only to fall prey to their destruction, locked away in the endless Abyss.Astroth Vermont lost it all, his will, his empire, his powers and his mind, all he knew was despair.But that’s until he woke up, Returning back to the world as someone else.The Blackest Evil was reincarnated as the Tenth Young Master of the Reinhart Family.His return is going to shape the world, returning all into chaos!Will he exact his revenge?Who knows, welcome to the land of carnage

Elena, who spent her entire life as a cold-blooded female knight to avenge her family, ended up dying without claiming her revenge. When she opened her eyes she found that she went back into the past. By day she was a lady in a dress, and at night she carried a sword to change history and prevent her family’s destruction.