In a world rife with deadly creatures called "youma", a young silver eyed woman, Clare, works on behalf of an organization that trains female youma halfbreeds into warriors with the ability to destroy these creatures. Considered a rogue for picking up a stray child and almost losing herself to her youma side by "Awakening", she is constantly assigned rather dangerous missions.
- The protagonist, Clare is a young member of the Claymores, a class of creature who is half human and half demons called Yoma , and whose quest in life is to fight against the full-breed Yomas -- hideous fiends who disguise as humans and feed ruthlessly on them.
The Claymores protect humans and fight against Yoma on behalf a mysterious organisation that created them and controls them. Clare's sole purpose in life and the reason for her becoming a yoma was to seek revenge for the loss that she faced when her loved ones were murdered by a yoma when she was a child and was abused and tortured by them till she was saved by a Claymore, Teressa, who was the strongest claymore alive then, to whom she got attached emotionally but who was later deceived and murdered and Clare must now avenge her death.
The organisation has a ranked hierarchy of claymore warriors based on their strength, Clare is the weakest as per the hierarchy but she constantly pushes her limits based solely on her will power and controls her demonic yoki powers like no one has done before and still manages to save her human side from being taken over and defeats the strongest of opponents. She fights to protect her friends selflessly risking everything for the sake of others.