Munashi danpen

The Munashi Danpen (虚し断片,Fragment of Emptiness) are an organization of individuals whose souls are stained by the power of "Emptiness". It was founded by Natsu Amakuni, who gathered a group who, like her, had undergone the affliction of having their souls stained. The power of emptiness is easily characterized by the now dense spiritual pressure an individual carries, rendering them immune to reishi absorption techniques. This organization is Natsu's sword to be wielded against the Soul King. Any soul or being is capable of being afflicted by Emptiness, regardless of the how one became afflicted.

History
A group founded after the second war between the Shinigami and the Quincy, it is a secret group who reside in the Dengai( due to the strain in their souls, they are uneffected by the current or the Cleaner itself, making it the perfect place to set up headquarters. While led by Natsu Amakuni, there is no defined hierarchy, so its members are left to their own devices, save for their intended goal to bring down the current establishment governed by the Soul King. Argus in particular has ulterior motives outside dethroning the Soul King and are currectly unknown.

Powers
Those who gain a foothold om their inner emptiness can access their Museigen nota jōtai (無制限のた状態, Unlimited state) forms. Its also possible to enter the state unconsciously through negative emotion, though it is dangerous because they can "inject" emptiness unto another individual if left unchecked, potentially staining their soul as well. This form is unique for Shinigami and Arrancar in that it merges with their respective Bankai or Resurrecion when mastered( in Natsu's case, it fused with her Teiki-teki kemono no katachi (定期的獣の形, Recurring Beast Form), though such a fusion is optional and the original Bankai/Resurrecion can still be accessed. However, for humans and Quincy afflicted the form reflects the reason ones soul was stained in the first place. Unconscious or not, however, the form is hard to mantain. Using the form anylonger than 15 minutes runs the risk of an automatic Soul Suicide, depending on one's endurance. Access to this form allows for: Enhanced Spiritual Pressure: This form is capable of a massive increase of potential spiritual pressure, as well as it becoming denser than in an average state. Kūkyo shahei(空虚遮蔽, Emptiness Shield): A spiritual energy armor materializes, further increasing defensive capable far beyond what normal Blut or Hierro could provide.

Trivia
The Musei nota jotai is actually punned off Blazblue characters "unlimited" variation, which are simply more powerful version of the character to play as...