After Entering the Shinobi World, I Harass Black Zetsu Every Day

After dying suddenly from staying up all night gaming, Ye Xue transmigrated into the ninja world with a Game System. If she maxed out every level on her account, she could come back to life and receive one wish. The good news: her race was the golden-bloodline "Vampire Progenitor" she'd paid for in the game. She could level up at rocket speed and grow stronger just by drinking blood! The bad news: she'd transmigrated into the era of the Ninja Sect. As a level 1 rookie, what was she supposed to do when she could only drink the blood of people with chakra? The Sage of Six Paths may be out of reach, but Black Zetsu is much better value! Ye Xue "reunited" with Black Zetsu, tricked him into becoming her meal ticket, then lay flat and waited for him to feed her. Black Zetsu at first: Big Sis, let's work hard together. We'll rescue Mother in no time! Black Zetsu later: I can't keep this useless big sister. She's got no ambition, and I can't count on her at all for the mission to rescue Mother! Black Zetsu was furious that his useless big sister refused to improve. He considered abandoning her more than once, but he couldn't quite bring himself to, since she was still a useful helper (and family). From the Ninja Sect to the Warring States period and then to Konoha, Black Zetsu's sunk costs kept rising. He regretted ever getting involved. If only he'd never acknowledged this big sister :) Ye Xue: Little brother, why hasn't today's meal arrived yet? Black Zetsu: ...Right away. loading Mission to rescue Mother progress (×) Get stronger by drinking blood progress (√) [Ninja Sect: What do I do when my little brothers are fighting each other?] Ikeda Yexue: I'm a spy, but from the start I'm a commoner in the Ninja Sect. The Sage of Six Paths is my teacher, and Indra and Asura are both my little brothers! Black Zetsu: Damn it, I'm the real little brother! [Warring States: What do I do when my big brothers love me too much?] Uchiha Yexue: I'm a spy, but from the start I'm a Uchiha prodigy. Madara Uchiha and Izuna Uchiha are my big brothers. Let's get the Nanga River squad going! Black Zetsu: The naturally evil Senju and Uchiha must never form an alliance! [Konoha: What do I do when everyone likes me?] Uzumaki Yexue: I'm a spy, but I'm running two secret identities. One starts as an orphan of the Uzumaki clan and somehow ends up with a bunch of doting big brothers. The other starts as a war orphan and rises to become a veteran member of the Akatsuki! Black Zetsu: I told you to go undercover, so how did you almost become Hokage?! PS: 1. Reverse-harem otome, with a heroine everyone adores across three lifetimes. 2. The heroine thinks like a gamer, is carefree, and only cares about getting stronger. 3. Black Zetsu gets bullied. From the beginning to the end, he's the one getting fooled and suffering all the bad luck. Theme: Create a beautiful world together with love and bonds.