Clare is the protagonist of Claymore, a warrior of the Organization who holds the rank of number 47, the lowest among her generation. Her origin is unique among Claymores, as she did not receive the flesh and blood of a Yoma, the very monsters she hunts. Instead, she volunteered to become a hybrid by taking in the remains of another Claymore, the legendary Teresa, making her only one-quarter Yoma rather than the usual half. This experiment was deemed a failure by the Organization, which is why she was assigned the lowest rank, considered significantly weaker than her peers.

As a child, Clare endured extreme suffering. After a Yoma disguised as her brother killed her family, she was forced to travel with the creature as its plaything, an experience that left her deeply scarred and initially mute. Her life changed when Teresa, a Claymore known as Teresa of the Faint Smile, killed the Yoma and freed her. Despite Teresa's cold attempts to drive her away, Clare persistently followed the warrior, seeing through her stoic exterior to the loneliness beneath. This persistence gradually broke down Teresa's emotional walls, and the two formed a powerful bond resembling that of a mother and daughter. This happiness was shattered when a young warrior named Priscilla, who had awakened into a monstrous being, killed Teresa. Holding Teresa's severed head, Clare made the fateful decision to have her flesh and blood implanted into her own body, dedicating her existence to vengeance.

Clare's personality is defined by a stark contrast between a cold exterior and a whirlpool of passion within. She initially presents as an aloof and duty-focused warrior, seemingly prioritizing the elimination of Yoma above all else. This demeanor is a direct result of her traumatic past and her singular obsession with killing Priscilla, which she views as her only reason for living. Despite her attempts to appear emotionless, she is deeply caring and prone to acting on powerful feelings. She can be reckless, hot-headed, and willing to ignore orders or rush into impossible situations, especially when the safety of others is at stake. Her enormous willpower, evident even in her childhood, drives her forward in the face of overwhelming odds.

Central to her development is her relationship with a human boy named Raki. After finding him orphaned and alone, Clare sees a reflection of her own younger self and allows him to accompany her. Raki, who refuses to fear her as a monster, helps to defrost her icy demeanor, reminding her of her own humanity. Their bond, and the promise she makes to reunite with him, becomes a crucial anchor, repeatedly preventing her from losing herself entirely when she taps into her monstrous power. Through him, and through friendships forged with other warriors like the determined Jean and the strategic Miria, Clare’s focus begins to subtly shift from a purely suicidal quest for revenge toward a desire to live and protect those she has come to care for.

In terms of abilities, Clare starts as one of the weakest warriors, but her unique constitution grants her one exceptional gift: acute Yoki sensing. Inherited from Teresa, this ability allows her to read the flow of her opponents' energy with incredible precision, predicting their movements and finding weaknesses in their attacks. To augment her low power, she acquires several powerful techniques. She receives the right arm of the former number two warrior, Ilena, which allows her to perform the Quicksword, a technique of unleashing a devastating flurry of blows at superhuman speed. She also learns the more controlled Windcutter technique from another warrior named Flora. Over time, Clare learns to partially awaken, transforming specific limbs into monstrous, blade-wielding appendages that grant her immense speed and power. Her fighting style is pragmatic and analytical, relying on these borrowed techniques and her own cunning to overcome physically superior foes.