Zenith

Left bitter and jaded after being betrayed by her fellow operatives, former agent Zero is reborn as Zenith, the daughter of a count in the Tioren Empire. Despite her disdain for aristocratic life, she does her best to attend school as a noble lady. But when a mysterious tragedy befalls a classmate and sets off a chain of misfortune, Zenith abandons her usual indifference to protect her friends. As her cold heart softens, Zenith may start to realize just how dangerous loving someone can be...

(Source: Tapas)