Kyōfukui

is a which modifies both inner and outside body of the wielder to a certain degree where they can sense and feed the emotion of fear. The organs of the wielder are modified to sense and consume the emotion of fear. The digestive enzymes of the body are also modified so it can convert the emotion of fear into physical energy, spiritual energy, or chakra, or all of them. It is notable that modified organs to sense and drain fear usually retain their original functions while modified enzymes do not. This ability is inherited by most descendants of Mayume clan.

The degree of modification is decided during the pregnancy and will not change after that. Even though it can be said that everyone experience different kind and amount of modification, the outcome can actually be expected because the variance is incredibly small. Almost every wielder possesses two modified organs; one to sense and another to drain the emotion of fear. Which specific organ would be modified cannot be predicted accurately, however, the percentage of enzymes modified is foreseeable. On average, half of the wielder’s enzymes are modified. Modified enzymes usually lose the ability to produce energy through normal means. Normally, the deviation is around 5%. There is only one in a million chance to be born out of the average or standard and those people are known as “monster”.

Abilities
The abilities of Kyōfukui is divided into three parts; sensing, draining and lastly converting. The first ability is sensing the emotion of fear with organs enhanced by the ability. The organs that are possible to be enhanced are eyes and skin. Enhanced eyes are equipped with special receptor to see fear while modified skin are equipped with special receptor to detect fear. Enhanced eyes are categorized as dōjutsu and widely known as "Kyōfugan”. Unlike enhanced skin, they have a special characteristic. They appear as “red eyes”, eyes with noticeable blood vessels. Each of the organ has their own advantage and disadvantage. Enhanced eyes are more efficient in term of sensing but cannot see through any thick fog or physical object while enhanced skin can detect fear from wide and far range but cannot locate it accurately like the former.

The second ability is absorbing fear with modified organs. There are three type of organs that can be modified for this purpose; mouth, nose and skin. Fear cannot be devour, drink, inhale or absorb like water by normal human, it can only be done by organs modified by Kyōfukui. Modified mouth gives the wielder the ability to devour the emotion of fear, modified nose gives the ability to inhale fear like air while modified skin allows fear to enter the body through the skin.

The third and the last ability is converting fear into energy with modified digestive enzymes. These special enzymes have the ability to consume and turn the emotion of fear into energy or chakra or all of them. Basically there are three type of modified digestive enzymes. First is physical-type which convert fear into physical energy, better known as stamina. Second is spiritual-type which convert fear into spiritual energy. Third is chakra-type which convert fear into both chakra, the combination product of both physical and spiritual energy. Most wielder has equal amount of all three enzymes, only the “monster” has unequal amount of enzymes.