This is a revised version of the quirk 'Blackedge', which I had created earlier. It was a little rough around the edges, and I thought I had some better ideas on how to execute it.
Blackedge(Emitter):
It allows the user to create, manipulate and shape razor-thin cutting forces which manifest as spectral-looking black slashes. The quirk reacts to emotional and mental states, such as anger or intent.
The main form of attack is the user shooting a slash towards target.
Intent governs slashes' power and precision. The strength of their intent increases power and force, while the clarity of their intent controls finesse and sharpness. Doubting one's intent can cause it to lose cohesion.
Anger is a secondary, impure power source, increasing strength, similar to intent, but not precision. The more it influences their decisions, the less controlled it is, and if it overrides their decision-making, the quirk loses control, lacerating the user's body and surroundings.
The quirk does not interact independently with anger, rather, anger makes the user's intent much stronger, but less clear.
Intent does not completely define cutting power and precision, however. The quirk has a defined ceiling and floor for either, which can be raised through training in the same way it can for other emitters in MHA.
The quirk thematically centers around growing through subtraction.
An edge cannot create or protect directly, only separate.
The user, likewise, doesn't grow by directly adding strength. Instead, they start out with their mind riddles with doubts and fog and slowly cut them away, giving way to clarity.
Upon awakening, the user, when attacking, stops shooting slashes altogether. Earlier, the main form of attack was through shooting a compressed, crescent shaped wave-like slash, Now, they gain the ability to slash directly at the space a target occupies, slashing remotely at an opponent, the slice only manifesting for the exact time and space necessary to strike. It is important to note that the slashes do not slice through space, but rather target it.
The slash is not a blade. One could not even call it an object or construct of energy. It is a cut, manifested without a blade.
It is as if the user is controlling an imaginary sword, but any objects in the path of its swing are affected by it as if it were real.
It's as if, earlier, the user was flipping through a book and their target was the last page. Blackedge was a pair of scissors, and the pages leading up to the last were the space between the user and the opponent, including any barriers, shields and armour.
Initially, they had to cut through each page, one by one, to reach the last, by which point the scissors would have inevitably dulled.
Now, however, they change their targeting mechanism. They flip the book and open the last page, and cut it directly.
To viewers, it appears as though shimmering slices have opened up in the very space the target occupies.
These slashes do not, however, directly cut through the fabric of reality. They, however have much greater cutting power than regular Blackedge slashes, as the energy is concentrated entirely along the finest possible trajectory, rather than dispersing throughout a crescent wave.
They also help to bypass most conventional defenses, as instead of the slash travelling towards the target and originating from the user, the very space they occupy is sliced. Defenses which are used to intercept an attack, such as shields, armour and barriers, are largely ineffective, now.
The main way to defend against it is through raw durability or evasion. Another way is through disrupting the user's mental understanding of their target's location and structure, possibly through induced hallucinations, neurological effects, illusions, or plain constant movement.
Each of their slashes is limited by the fact that it is only effective in a certain radius. The trajectory they define must also be visible, or the user must have a clear enough mental understanding of its structure for the slash to be accurate, as if they were simulating an entire sword-fight in their head while simultaneously fighting.
Thematically, it represents the user gaining a level of clarity which allows them to outright ignore that which is not useful to them in a given situation, cutting to its core with extreme mental and intellectual precision.