The Cursed Blades of Vengeance are sickle shaped blades that cursed anyone who received even the smallest wound from them to be doomed to fatal misfortune.
During feudal days of Japan, the blades were owned by twin sisters. When an evil warlord slayed their family, the sisters used the blades to kill him in retaliation. The blades were cursed anyone injured by them, to be doomed to face death at every opportunity. One night in New York City, a fox-mutant named Alopex stole them from a museum, intending to use them on her brother Tiger Claw. Raph and Casey tried to stop her, but Alopex ended up cursing Casey with the blades. She then used them to confront Tiger Claw, but she was forced to flee.
When April, Casey and the Turtles later confronted her about her vendetta against Tiger Claw and asked to help lift the curse, and she revealed that the only way to reverse the curse was for Casey to use the blades to injure her or destroy them. However, she told them that neither would happen until she had her revenge. She fought Tiger Claw, but he managed to trap her and prepare to use the blades to kill her, but the Turtles freed and helped her fight Tiger Claw. During the fight, both the blades were frozen by Tiger Claw's freeze ray gun, which made them brittle enough to be broken, thereby lifting the curse on Casey and Alopex defeating Tiger Claw by slicing off his right arm.