Transparent World

The Transparent World (きる) is a special supernatural ability unique to and can only be accessed by Demon Slayers that have awakened the Demon Slayer Mark.

Overview
Demon Slayers that have awakened the Demon Slayer Mark can utilize a special form of extrasensory perception ability, altering their vision, perception and even augmenting their physical abilities slightly. The user becomes able to see the muscles, blood flow, and joint movement of living beings, allowing the user to accurately predict and react to their opponents movements, as well as confirm the well-being of others. Additionally, the user gains hyper-perception, allowing them to perceive the world around them at a much fast rate, making it appear to them as if the world was going in slow motion. This ability originated from one of the powers gifted to Yoriichi Tsugikuni and was passed on from Demon Slayer to Demon Slayer through his Demon Slayer Mark.

The Transparent World is most likely an ability created for the specific purpose of extermination of Muzan Kibutsuji as users would be able to instantly understand the properties of the Demon King's body, and surmise how to defeat him.

It is unknown how users will be able to access this world as the numerous instances where this ability is utilized differs. For Tanjiro Kamado, he accessed it through a memory of his father, Tanjuro Kamado, teaching him how to use it. For Gyomei Himejima and Obanai Iguro, all they had to do was to focus all their energy on their eyesight alone, allowing them to access it. For Muichiro Tokito, it is unknown how he managed to access it, but it was hinted at that he started using it after he awakened it during his battle against Kokushibo. In Yoriichi Tsugikuni's case, he was born with the ability, being able to use the ability when he was a mere child.

Abilities
Penetration Vision: The main ability granted to users of the Transparent World is a special variation of extrasensory perception that is in the form of a modified ocular power that allows the user to view all biological entities they are looking at as transparent, only leaving their muscles, blood flow, and joint movement visible, as well as a faint outline of the being they are looking at.

Hyper-Perception: The Transparent world also grants its user's a heightened and quickened vision and perception, being able to view the world in slow-motion, greatly augmenting their reflexes and speed.