The Yin Yang Soul

Lian Cai Yi has it all, not only is she the Eldest Daughter of of the South Prime Minister of the Sheng Kingdom, her grandmother was the doted on blood younger sister of the current Empress Dowager. She even has the greatly desired Wood and Fire Spiritual Roots, enabling her to learn medical crafting. The only blemish on her reputation her waste of a half sister, Lian Xie Mei, the result of her father's drunken mistake. She grew up greatly doted upon to be a beauty that could cause the fall of cities, her fiance the one and only Crown Prince, she even chased off her useless younger sister. Eventually the Emperor died, and on the eve of the night that she was to be crowned Empress, Lian Xie Mei returned.
It turned out her younger sister wasn't a waste, she had the holy trinity of Spiritual Roots, Fire, Wood, and Metal, letting her learn not only Medical Crafting but Weapon and Armor Crafting as well. She was even at the peak of the Foundation Establishment Realm 5th Stage! If she was a waste then what did that make Lian Cai Yi trash?! Lian Xie Mei immediately took over the capital city and threw her in the dungeon where she explained everything. Her younger sister had actually long been dead her soul taken over from someone from another universe.
Sitting in that dungeon dying slowly from a poison she was forced to swallow filled with malice and rage she used a secret technique that she had managed to catch a glimpse of in her Master's notes to send herself back in time to her 12 year old self. This time she will win! This time she will beat that trash half sister into the ground! This time she will stand at the peak of the world! But will things really be that simple?