MSZ-034 Heroine Subjugation: Pretty Soldier Sailor Sharon Episode 0 ~The Blue Rose That Bloomed in the Darkness~ by Aikawa Nui

Ayumi Mizusaki, a high school girl with an IQ of 300, is a beautiful girl with a modest personality but an exceptionally strong sense of justice. One day, Ayumi saves someone from an attack by the monster Zardon, but loses her life in the process. However, she is resurrected by the sea god Poseidon, who grants her the power to transform into a warrior of justice, and she takes on evil as the beautiful warrior Sailor Sharon. Initially bewildered, Sailor Sharon decides to walk the path of a warrior in order to protect people. But a harsh fate beyond Ayumi's imagination awaits her on that path... [BAD END]