Demon Weapons (魔武器, Mabuki) are human beings who have the ability to transform into a weapon. At the DWMA, they are paired up with Meisters, humans who are able to wield them in their Weapon forms. Together, they can achieve a greater amount of power than they would on their own.
The first Demon Weapons were created 800 years ago prior to the start of the series, Arachne following instructions found within the Book of Eibon. To create a Demon Weapon she murdered a Witch to use as a sacrifice. Using the Witch's soul, which has the power of transformation, Arachne joined together an inanimate weapon and a human soul to create a Demon Weapon which had the ability to transform from Human to Weapon form. This act of killing a witch made every witch want to kill Arachne and demon weapons alike. One of the very first Demon Weapons to have ever been created by Arachne is suggested to be Giriko. The Demon Weapons, despite their unplanned creation, were accepted into the world, and the Eight Powerful Warriors were the first people to fight as Weapon and Meister teams.
The blood of a Weapon is passed down however depending on the circumstances of an individual's life that blood may or may not actually be awakened. There are families like the Nakatsukasa clan which are made up entirely of Weapons and families like the Evans family where the Weapon Soul is apparently the only member to have inherited the Weapon blood for numerous generations. There are also very rare cases, such as Maka Albarn's, for instance, who is a Weapon and Meister hybrid by having a Demon Weapon father and a Meister mother. She briefly activated her Weapon abilities while unconscious (this is only the case in the anime, and has not been mentioned in the manga).
Wavelength communication: Allows communication on a spirit level with meister and, most importantly in combat, allows them to receive or give energy.
Metamorphosis: Main fighting power. Transforms part or all of body into a set weapon.
Multiplier: Allows them to multiply any energy they are given. Note that, unlike meisters, they are incapable of generating energy of their own and are thus far weaker when fighting alone (higher level weapons can fight solo see Autonomous weapons).
Elemental : Converts energy they are given into a set element such as fire, electricity or a slicing attack. Not generalized skill.
Polymorphosis: Higher level weapons or hereditary skill only. Allows for more than one transformation.
Soul Eater : Allows them to eat/absorb (or regurgitate) the soul of a vanquished foe in order to make them stronger.
Humans with active Demon Weapon genes look like pretty normal humans (except for Ragnarok and Excalibur). Their type of weapon they are and the weapon's appearance seems to depend on various criteria. For example, it could depend on a person's personality (Giriko, a violent Demon Weapon who loves to kill, takes on the form of a chainsaw) or it could be the region one was born in (Tsubaki, Masamune, members of the Nakatsukasa Clan are all Japanese, and take on the form of Japanese ninja weapons and a katana), or in the case of very old weapons, what time period they were born in (Excalibur, who lived in medieval Britain, turns into an arming sword, while Ragnarok, from Viking Scandinavia, can become a Viking broadsword in his big form, a berserker sword in his Black Dragon form and a longsword in his shrunken form). Weapon types are very diverse, with typical weapon types such as swords, shurikens, guns etc. along with more obscure ones such as mirrors, lanterns, and even 'pots.' When addressing Demon Weapons, the Japanese word for 'demon,' 'magic,' or 'demonic' (魔 Ma the same kanji used in the Japanese word for Witch, which is quite suited to Demon Weapons since they were created by them) is put before their Weapon forms. For example, Soul is known as a Demon Scythe. The way a demon weapon consumes the souls vary individually, with some weapons such as Soul and Ragnarok literally eating the souls, chewing and swallowing, while other weapons absorb through more unique ways such as Liz and Patty absorbing the souls to their magazines when transformed and Nigus sucking the souls to her scabbard before being sheathed.
Some Weapons in their Weapon form have certain components that move similarly to facial expressions; such as Soul, whose Weapon form has a red eye on top of the haft, which can convey his mood by narrowing when he is angry or ready to fight, or widening when he is startled. Ragnarok's Weapon form has a mouth on the blade near the guard. In Weapon form, Demon Weapons are usually invincible, and although they can feel the impact of the clashing with physical objects, they are protected by their Weapon form and cannot be hurt, unless they are hit by something extremely powerful. If that is the case, the Weapon can still be injured and can bleed, even in Weapon form.
Transformation from Human to Weapon
When becoming a weapon, their clothing and everything on their person is carried on into the transformation. After becoming a weapon, the person is seen in his/her human form as some sort of reflection on the weapon and is seen in a completely black space when viewed inside the weapon. Inside their weapon, Demon Weapons seem to be able to have easy access to their souls, as Soul Eater can enter the Black Room in his mind from his Weapon form. They are still able to verbally communicate in their Weapon forms.
Often, in this dark space they are seen without their clothing on, save for a few details (Harvar appears with his visor on). In other cases they can be seen with their entire clothing. If two Weapons are resonating together and/or close together i.e. they are both used by one Meister, they can share this dark space. The Weapons also glow in the color of their souls when inside Weapon form. For example, Soul Eater has a blue soul, as such, he is glowing a light blue in the dark space. Tsubaki has a yellow soul, therefore she glows yellow. The Thompson sisters have pink souls, so they glow pink. This glow is also present when the Weapons are transforming. The transformation usually involves the Demon Weapon being engulfed in a bright light (the light is the same color of their souls) and changing into the shape of their weapon before the light disappears. Elemental Demon Weapons display their elements when transforming e.g. Harvar turns into lightning when transforming into his Weapon form. The same also goes for Weapons with various 'themes.' Nygus is often associated with bandages, and her body dissolves into bandage-like strips when she is transforming.
Transforming into Weapon forms can be quite hard for rookie Demon Weapons. Some can only transform parts of their body, or cannot transform at all. The key to transforming, according to Sid, is to picture the weapon resting in one's soul. Mostly, it has to do with confidence and willpower.
These transformations also showed an useful side as Liz and Patty, two demon weapons were wielding each other during Kid's absence in the pyramid, they used it as evasion, transforming themselves between weapon and human in order to evade the mummies's attacks, showing that, somehow, demon weapons can also transform themselves straight to their intended wielder's hands.
Demon Weapon Discrimination
Demon Weapons who are still inexperienced in utilizing their abilities are known to accidentally hurt the people around them when their transformation goes wrong. Therefore, they are often feared and discriminated against by normal society, although they pretend to admire them. This is one of the reasons why the DWMA is built, to take in these Demon Weapons and train them to have full control of their ability so that they can be accepted and respected in society.
Types of Demon Weapons
Most Demon Weapons are able to transform into Weapon forms, and transform a part of their body into their Weapon form when fighting on their own. However, they are not much of a threat. However, with a Meister, a Demon Weapon can unleash its full potential by combining their strengths with their Meister's. Some Demon Weapons have special characteristics, such as the Nakatsukasa Clan's multiple Weapon form transformation. Some Weapons can also have elemental properties, such as fire and lightning, and can generate these elements even on their own.
Demon Weapons are known to have a 'true form.' As a human soul and a Witch Soul was needed to create the first Demon Weapons, if a Weapon consumes a certain amount of Evil human souls and a Witch Soul, they turn into a powerful Weapon known as a Death Scythe. Eating a human soul, however, will cause the Weapon to turn into a Dark Weapon. This transformation seems to remain permanent, even after the consumed souls are removed. If the consumption human souls continues and the dark weapon consumes a witch soul after sufficient humansouls have been consumed then the dark weapon becomes a Demon Sword
It is interesting to note that normal weapons can transform partially by replacing a body part with the blade (Soul transforms his arm, Tsubaki her hair, Harvar his hand) while Death Scythes can burst weapon parts out of their body without replacing anything (Spirit out of his arms, like Justin Law, and when Soul becomes Death Scythe he also can burst a blade out of his arm, without replacing anything).
The Bond Between Weapon and Meister
|“||A Demon Weapon is a Demon Weapon when fighting alongside their Meister. You're never alone...||”|
—Soul, Chapter 76
At the DWMA, Demon Weapons are paired up with Meisters, skilled humans with great combat skills. With the Weapon's ability to strengthen their Meister, and vice versa, a Weapon and Meister team can combine their respective powers to become near unstoppable in battle. They can also make each other stronger by working together, making the bond between Weapon and Meister a strong and close one. In order to work together properly, the Meister must understand the Weapon's will, and vice versa. The Demon Weapon is not a normal weapon, or an inanimate object. It is a person with objectives. When perfectly in sync with each other, they can become a lethal force. Just by matching their breathing, a Weapon and Meister can fight flawlessly.
When paired with a Meister, a Weapon becomes extremely deadly. By performing resonance between a Meister and a Weapon, the Weapon can unleash a variety of abilities and can even change its physical form. This level of power can be achieved through what is known as a Soul Resonance, where both Meister and Weapon synchronize their souls with each other. In this state, their thoughts are both synchronized so well, that Weapons can even react to their Meister's emotions (Jackie fires out flames when Kim gets angry in her fight with Ox.
In theory, there is no restriction on who is capable of wielding a Weapon. Apart from meisters, it has been demonstrated that many other beings can wield a weapon: other Weapons (Liz and Patti Thompson can act as each other's meisters), animals (the Death Scythe Tezca Tlipoca is wielded by a monkey), Witches (Kim Diehl is an example) or even a soulless creature with a soul implanted within (Giriko was once wielded by the Oldest Golem while it contained the soul of Arachne). However, in practice, the wielder's soul must be able to align with that of the Weapon or a rejection reaction effect will occur. This reaction is derived from a misalignment in the users' Soul Wavelengths, resulting from incompatible personalities, and appears to differ depending upon the individuals involved. For a Weapon and Meister to be compatible, they have to be able to accept and understand each others' personalities. Most compatible Weapon and Meister pairs seem to be opposites in personalities, especially seen with Black☆Star and Tsubaki, and Ox and Harvar. People with similar personalities like Soul and Black☆Star cannot become an efficient team. So far, Soul and Ragnarok are the only ones to show a rejection reaction though.
Symptoms of this rejection seem to vary on how much the Wavelengths are incompatible. When Black☆Star tries to wield Soul, their Wavelengths were so incompatible, that Black☆Star could not even lift Soul from the ground, and when Black☆Star sent his Wavelength through him, it caused the Demon Scythe physical harm. In the brief moment when Maka couldn't resonate with Soul, the rejection reaction was milder, but still harmful, as even though Maka is able to wield Soul, his Weapon form is extremely hot to the touch and she severely burns her hands until she can resonate with him again. Ragnarok's rejection reaction affects Crona as well as they both share the same body, and when their Wavelengths become misaligned, dozens of Bloody Needles erupt uncontrollably from Crona's body and the pair loses their ability to utilize their Black Blood. A rejection reaction can be taken so far up to the point that a Weapon and Meister permanently lose their ability to synchronize their souls. At the DWMA, Weapons and Meisters can also change partners if they wish.
At the DWMA, the duty of the Weapon is to protect their Meister at all costs in battle. Seeing as how Weapons do not play as great a fighting role as does their Meister, it is common for them to be in the shadow of their Meister, as noted by Ox while he is observing Patti sparring with the other students. They are often more renowned once they become Death Scythes. In a Meister and Weapon partnership, the Meister is also the dominant figure, as the Meister's decisions are often considered instead of a Weapon's, and Weapons also have a duty to follow their Meister's commands. However, some Weapons break this duty, mostly because they view their Meister as not just a partner, but a close friend, so in order to ensure their safety, they sometimes refuse to obey their Meister's commands and criticize their decisions.
- A common inconsistency in the anime is those who can eat Souls. The anime and manga both explain that only Demon Weapons can eat souls. In the anime, people such as Lupin, White*Star, and Al Capone, and Jack the Ripper contradict this. However, in the manga, there's no mention of any of these character consuming souls. All of their crimes are those like Thievery & Murder. No characters mentioned above have actually consumed souls within the Manga version of Soul Eater.
- Only Asura has been able to eat a soul and he's classified as a Meister. However, due to his eccentric abilities, he consumed Vajra & resonated to gain the ability to consume souls.