Death Scythe (デス・サイズ, Desu Saizu)
Death scythe (デス サイズ, desu saizu) are the most powerful weapons in Soul Eater. They are weapons that have earned the right to be wielded by Death.
In light of the sealing of Asura, Death cannot travel, prompting Death Scythes to be stationed all around the world, so they can maintain the peace and be used by high level meisters, if need be. So far in the story, there are a total of nine Death Scythes, with eight each in charge of a different part of the world. Of the eight regions, six are known: Europe, Oceania, East Asia, North America, South America, and Africa. Of these six regions, only five Death Scythes are known (as the one for Africa refused to return to Shibusen).
Achieving Death Scythe Status
For a weapon to become a death scythe, they must quest and eat 99 Souls that are on shinigami-sama's list and one Witch Soul. The Witch Soul is the hardest soul to capture and so is normally done last. If a Witch Soul is captured before gaining the other required souls, it is held within Shibusen until the correct number is met. If a soul other than a Witch Soul is eaten last, such as a Cat's Soul (In Maka and Soul Eater's cases), all the previous souls will become worthless and the quest must be restarted. Once a weapon has achieved Death Scythe status, the weapon in question will undergo a few changes in weapon form.
Justin Law was once known as the youngest Death Scythe and is so far the only weapon to become a death scythe without a Meister partner. Although, it now appears Soul would hold the record of being the youngest Death Scythe.
In the anime there isn't a shinigami list, instead the weapons have to eat 99 souls that are on their way to becoming a Kishin. This fact lead to some changes, per example Mifune not being stated as having a Strong Soul. Instead Black Star was supposed to collect the 99 souls of Alcapone's gang which Mifune had killed after they attacked him.
Special Abilities
By consuming the final witch's soul a Death Scythe is granted numerous powerful abilities. This is achieved by the advanced wavelength control gained from the witch's soul that has been obtained, which can give rise to magical abilities, manifesting further special abilities.
Among these abilities, form manipulation is noted as not only a standard trait but also one of the most basic. However, it can give rise to powerful and useful techniques such as when Soul demonstrated the power to create wings of light, for flight, by focusing on achieving the same goal as Maka.
Death Scythes also gain special abilities depending on the Witch's Soul they eat. For instances Soul is able to use "Adagio of the Soul" using a net to distribute the music, because he ate Arachne's Soul.