"...It's fine if I want to live."
Flamme was chosen to join the hero's party even though all her stats were zero. The only thing she had was an ability with no known effects, "Inversion." It was completely worthless in combat, but even still, she wasn't discouraged and did whatever she could for the party. However, the famous genius sage Jean was unsympathetic and did whatever he could to drive her out, finally resorting to selling her into slavery.
Even at the slave shop, Flamme was persecuted endlessly, finally being fed to horrific monsters just to serve as entertainment. However, when she picked up the "Cursed Greatsword" that was supposed to melt her body away, her life was quickly 'inverted.'
The curse turned into a blessing, and her despair became inverted—this was the start of a dark fantasy interwoven between two young girls!