Due to their hybrid nature, Claymores possess strength, speed, and reflexes far greater than that of any human. Because of their great strength, Claymores can wield a heavy claymore single-handed with ease and grace. In addition to this, Claymores possess vast regenerative capabilities and resilience, allowing them to survive normally-fatal injuries such as evisceration. Any wound that does not kill them heals over completely within hours. Claymores with a talent for regeneration, such as Deneve, can even regenerate entire limbs within minutes. These abilities, combined with their combat training and weaponry, allow Claymores to fight on par with most Yoma.

Aside from their strength, perhaps the most well-known ability wielded by Claymores (and the one for which they are most prized by their clients) is their ability to sense Yoma. This is achieved through the sensing of Yoki (Yoma energy). Specialized Claymore can detect the aura of a Yoma from as far as several miles away, depending on the individual Claymore's skill. Clare herself has proven capable of sensing residual Yoki on humans who come into close contact with Yoma. A refined use of sensing Yoki allow the Claymores Teresa and Clare to read and predict the Yoma movements, to the point of reacting before the Yoma attacks. Some claymores can use their sense of smell to locate yoma. Clare and Miata have exhibited this ability.

All of a Claymore's abilities are dependent upon her control over her body's Yoki. By regulating the amount of Yoki used or localizing it to specific body parts/functions, Claymores can further augment their already-prodigious physical attributes, or utilize a number of exotic abilities. The average Claymore will tend to simply tap/release a greater percentage of their total Yoki, causing great increases in base strength, speed, and healing ability. If a Claymore releases 10% of their power, their eyes will gleam gold and become cat-like. If they release 30%, their face will contort and become monstrous. If they release 50%, their body will deform. Tapping too great an amount (over 80% of the body's total Yoki), however, causes Claymores to become Awakened (see below). Higher-ranking Claymores usually display far greater control, and exhibit enhanced ability with their standard abilities or unique powers, such as Ilena's Quicksword, or Helen's ability to extend her arms.

Claymores require far less food in order to survive than normal humans. They need only consume a few bites of food every few days, and if required, can go for over a week without any. Partially awakened Claymores occasionally feel hungry. They are generally only seen resting by sticking their claymore swords into the ground and leaning against them, rather than sleeping in a lying position or on a bed. In terms of physical appearance, most Claymores appear fully human save for their silver eyes and pale hair (extremely weak Claymores can retain some hair color). However, some possess inhuman traits such as pointed ears. Early in the manga, it appears that the front of Teresa's torso is hideously deformed, although we never see it directly. However, when we do see Jean's, later, no deformation is seen. This discrepancy has not been explained.

Almost all Claymores are created against their will, only becoming Claymores because they had no other way to live. Many are orphans, abandoned children, or survivors of towns and families attacked by Yoma (although the Organization has been known to take children from their family, if they have an unusual quality they desire). The only known exception is Clare, who asked the organization to put Teresa's flesh and blood inside her body in order to become a Claymore and take revenge on Priscilla.

The Claymore organization has a strict hierarchy, in which the Claymores are each given a rank corresponding their relative strength. Claymore #1 is the strongest, while #47 is the weakest (and receives a corresponding lack of respect). The number of existing Claymores at any time is officially 47 as that represents the total number ...