Saa, Akuyaku Reijou no Oshigoto wo Hajimemashou: Moto Shomin no Watashi ga Idomu Zunousen

Would you become the villainess to save your beloved baby sister? That was the deal promised to Mio Satou by Shizuki Sakurazaka, heiress of the Sakurazaka Group, one of the most powerful conglomerates that dominate modern day Japan. The terms? Take her place in life. Survive three years at an elite academy where the progeny of tycoons and moguls roam, and in return, Shizuki will cure Mio’s terminally ill sister. (Source: Cross Infinite World)