Weapon transformation is a simple technique involving humans and guardian spirits, in which the guardian spirit physical transforms into a weapon for their human partner to wield in battle. It is an easy technique to master, but difficult to achieve if the partnered human and spirit have a very low compatibility with each other. By combining their powers in such a way, the pair can achieve a greater amount of power as opposed to fighting on their own.
Weapon transformation is when a guardian spirit physically transforms into a weapon to be wielded by their partner or another human of their choice. While their mobility is largely now dependent on their partner, by combining their power with that of their partners, they can achieve a greater power altogether.
While most members of the Masanari Black Flowers use regular weapons, they will move to using a weapon transformation if needed. The reason they do not use weapon transformation all the time is so that they are not always reliant on a sentient weapon to act for them and learn to handle themselves.
Unlike Beast Fusion, weapon transformation is far easier to handle and master. In fact, it is rare for an individual to fail in maintaining their guardian spirit partner's weapon form, though this can result from lack of focus and concentration and more importantly, incompatibility.
In order to utilize a weapon transformation to its fullest potential, both parties must surrender their wills to each other to form an unbreakable bond and act in perfect synchronization. Upon achieving this, the two become an unstoppable force of great power and determination. This allows them to not only fight as they would with their regular weapons, but also utilize their guardian spirit's elemental abilities in tandem with their combat.
Weapon transformation has few weaknesses aside from being eclipsed in power level by the much more difficult and destructive Beast Fusion.
Because the wills of the two parties involved are so linked together, if one will was to falter or become weak, the will of the other would falter as a result and their synchronization would fail. Disagreement can also affect their ability to optimally perform. If the pair were to disagree on how to handle a situation, their abilities and power would falter greatly.
Out of the two, the human partner can be considered the dominant partner as they are wielding the guardian spirit in weapon form. Guardian spirits can be known for their disobedience and arrogance as some view themselves as superior to humans and feel that they should not be commanded by them. As such, the two can fall out of sync. Guardian spirits may also be disobedient for noble reasons, such as wanting to protect their human partners or even criticizing them.
- Weapon transformation is based on Demon Weapons from Soul Eater.