I'm No Saint, So I'll Become the Demon Lord!

Rina Amakusa, worn out from working at a toxic company, finds herself guided by a mysterious voice and suddenly transported into the world of a game she once loved, taking on the role of a saintess. She tirelessly repeats loops, striving to save the world, but her life takes a dark turn when she is betrayed and killed by her favorite character. Her love for him twists into hatred, and that transformation shifts her from saintess to final boss. Thus begins a tale of revenge in an otherworldly fantasy setting!