Noroi no Maken ni Yamitsuki Otome / 呪いの魔剣に闇憑き乙女

Long ago, this continent was peaceful, until the black mist enveloped the kingdom, making all those who touched it pain. The citizens believed that this was the work of the Lord of the demons, and they became afraid to leave their homes. When the beautiful princess also fell ill, the king begged someone to defeat the demon lord in return for the reward. One young man offered to do it in exchange for the princess's hand in marriage. Together with his friends, he defeated the demon lord, who vowed to resurrect once to take revenge. The young man returned to the cries of people who called him "a hero."
Claire very much admires the hero who saved the world and, thus, she set out on the path of an adventurer. However, for such newcomers there is not much work, so she works part-time at the store of Lena's magic items. Once she came across an old magic sword in the store. When she took it out of curiosity and waved to them, a dark glow began to emanate from it, and a demon beast appeared! Before she was able to prevent this, the beast fled the store. Not only that, but the sword cursed her. With the help of the former adventurer, Lena Claire embarks on a risky journey to cast aside the darkness and get rid of the curse of the sword.