Bisection

**Bisection** (半減, *Hangen,* Lit; *"Reduction By Half"*) is the name of the Quirk used by Sayumi Irozaki. It is an Emitter Quirk which allows her to perfectly halve all manner of objects that she comes into physical contact with.

## Description

### Overview

Bisection is a powerful and lethal Quirk which is functionally defined as an Emitter Quirk ability. It grants Sayumi the power of perfectly reducing many forms of matter and phenomena in her surroundings by exactly 50%, leaving only half of the object left. An ability that is inherently offensive in nature, Bisection is a Quirk which Sayumi has manifested in the form of an extremely powerful cutting ability, and it permits her to easily cut through objects and targets that would normally be extremely durable or otherwise completely invulnerable against being cut. For example, she is more than capable of easily cutting entire buildings in two by making some form of physical contact with them, or slice apart oncoming enemy attacks of varying different forms and types, even those that would normally not be capable of sustaining any kind of cutting damage. Startlingly, her Bisection power is something that can be used on both physical and non-physical objects. By cutting the time it takes for her to execute a movement in half, she can drastically boost her movement and attack speed, or by cutting the distance between herself and her enemy, she can achieve levels of unnatural physical speed which can be quite overwhelming for her opponents, to the point that she even seems to be teleporting. She can even cut through the bodies of human beings by halving them, leaving them in two pieces as a result.

Sayumi is also capable of cutting things in half multiple times. She has demonstrated the ability to halve a boulder that is larger than her by several times to the point that it became a pebble that fit between her finger and her thumb. This is done by her halving an object, leaving only half of it left, and the halving that object, continuously subtracting from its form and mass. This allows her to severely lower and diminish the power of the attacks launched at her by her enemies. In a method of defensive application, Sayumi can also use her Quirk to cut the attack power and general kinetic energy down, in such a way that she becomes capble of catching the fist of an opponent many times larger and naturally more powerful than her in the palm of her hand as though it were weightless. Sayumi has even implied that she could perhaps cut down a substance to the point that there is virtually nothing left of it, though she has not shown any kind of power on this level as of yet.

### Weaknesses

Though it may be powerful, Sayumi is far away from having reached complete mastery or the full power that her Quirk can offer her. It is far from an absolute power. Though she is capable of effecting non-physical phenomena with her willpower, the effects of her Quirk in the way of effecting tangible or semi-tangible objects can only be initiated once Sayumi has successfully achieved some form of direct, or at the vey least, an indirect physical contact with her opponents and targets who are of strictly physical nature. If an opponent is capable of successfully evading her touch through for whatever reason, they are theoretically immune to the threat of her Quirk. Living creatures, particularly human beings, are the absolute most difficult targets for Sayumi to successfully Bisect, to the point that it is extremely unlikely that she can actually cut a person in half in one shot. It is shown to directly depend on multiple facets of a targets strength. Foes who are weaker and more frail than her are more easily victimized by her Quirk, but stronger opponents, such as most professional heroes, are extremely unlikely to be cut down by Sayumi. She becomes incapable of performing a complete bisection, instead leaving numerous cuts and lacerations on the bodies of her opponents. The most she can achieve against such figures is an enhanced form of cutting power, and even that can be rendered useless depending on the type of foe she is facing. Opponents with enhanced durability are particularly strong in the way of resisting her Quirk. In order for her to actually cut even a single human being in half, she would have to spend a dangerous amount of her own willpower, stamina, and general physical energy all at the same time, thus leaving her in an immediate state of exhaustion afterwards, rendering her incapable of fighting. Even then, there is no promise that her target will actually suffer the full effect, as there are many forms of possible defense that can be set up in order to guard against or absorb her Bisecting attack.

In addition, the effects of Sayumi's Quirk are not constant. Simply put, she cannot bisect everything at once, or without limitation. It is possible to wear her down and make her incapable of using her Quirk entirely. This is due to the inherent fact that using her Quirk requires stamina and physical energy in the same way that an athlete uses their energy to endure in competition. It is not endless and must end at some point. Opponents that can outlast her for extended periods of time can tire her out, thus forcing her to retreat at the risk of Sayumi herself becoming completely exhausted. As well as this, objects either physical or otherwise, the most that she can cut in half are measured in handfuls at a time, and attempting to cut in half more objects than she can keep track of will result in a drain on her stamina much more severe than usual. Inanimate or non-corporeal objects are much easier for Sayumi to cut in half, but even they can reach the point of being too much for her to handle once a certain point has been reached. Attempting to bisect exceedingly large objects or too many different objects at once can pose the threat of taking a dangerous chunk of stamina out of her, for example bisecting a mountain can leave Sayumi badly fatigued and thus lower her fighting abilities in the same way as a pro boxer who is fighting to go the distance against his opponent, while bisecting something as large as an asteroid, just one time, can leave her in a near-death state due to the severe drain on her body. The absolute most that Sayumi has ever successfully Bisected was a good chunk of planet earths atmosphere, though that act immediately left her in a state of critical condition that was so bad that she had been considered clinically dead at one point, and it was only thanks to the fast and well-prepared actions of her comrades that she actually survived, though she was left in a coma and hooked up to the greatest life-sustaining machines for several weeks before waking up. Additionally, even pushing the power of her Quirk to its absolute limit and piling on supreme effort on top of that, she could not reduce earths atmosphere by 50%, thus this feat is considered one of the numerous examples of her ability failing, however impressive it may have been considered at the time that she had performed it.