Yohan Kokuchouin is the leader of all the Ura-Fuuchouin and ruler of the Sodomunado. However he is biologically the younger brother of Kazuki Fuuchouin of the Omote Fuuchouin clan.
Yohan is shown to be highly intelligent. By the age of six, his wisdom and understanding of the world was on par with a sage. He is an absolute genius. His talents are off the scale in every category. He is quick-witted, observant, intellectual and intuitive; rarely being caught off guard or deceived. Cruel, ruthless and confident in his abilities he remains composed and unconcerned with the situation at hand. Even when the raging fires and dead bodies of his fellow clan members dropping around him, he showed no emotional build up. Yohan displays great indifference to those around him. Feeling superior to all of them, including his own family. They say he was born at midnight like a demon, and he didn’t shed a single tear. During his first bath his gaze was like that of a king. As if all those around him would one day be his servants
Yohan was born to the Fuuchouin head family and could speak words immediately. This was seen as an ill-omen as he could make a potential enemy of Kazuki in the future so his father initially wanted him killed. However due to their mother's pleas, Yohan was secretly adopted by the Kokuchouin family. As for Kazuki, he was told that the child was still-born. When he was young, Yohan's father asks Kazuki's father to let Yohan be the head of the family since he was possibly the most talented Fuchouin ever; but Kazuki's father declined the offer.
Yohan matured at roughly twice the rate of growth that should be typical with his relative age group. At the age of 6, Yohan then became the leader of the Ura-Fuchouin and soon after that they began their revolt against the other houses of the Fuchouin. In addition to mastering all the techniques of the Fuuchouin-ryuu as well as the art of Onmyōdō Yohan researched extensively into the history of the Fuuchouin clan. It was during this time that he discovered the clans’ connection to the Five Tribes of China.
Through the connections of the Ura-Fuuchouin Yohan discovered another name connected with the Tribes, Ranma Saotome. Ranma Saotome had defeated the leaders of each and every one of these tribes. It was here that Yohan realized that in order cement his supremacy amongst the Fuuchouin and all those connected to it, he would have to kill this warrior. However his plans changed upon the discovery of Ranma’s Jusenkyo curse he would not kill Ranma Saotome he would make “her” his wife. Yohan saw Ranma the same way he saw his brother Kazuki. He saw hatred as simply a form of love. Where others only hated him out of fear Kazuki and Ranma would be the only ones capable of truly hating him. By birthing the new heir to the Ura-Fuuchouin, Hatred fear, despair Ranma would keep piling up new negative emotions, one after another. And in the end Yohan would drink them all up. Along with the last dying sparks of Ranma’s life. Such is the will of Kokuchouin Yohan.
Yohan Kokuchouin is the greatest sin the Kokuchouin line has ever brought into this world. Born with the soul of an elemental granting him the ability to tap into his Lei-Line core to affect the flow of elemental energies in his immediate environment his power transcends what can be achieved by normal humans and warriors.
An unrivaled genius in battle, Yohan mastered the Ura-Fuuchouin art at the age of 3. He is made even more dangerous by his Shingan. He has developed his sixth sense to full Clairvoyance with all the abilities associated with it. Yohan is able to look beyond the form, beyond the impression to the reality that underlay them to perceive beyond what is physically possible. Through the Heart of Eyes Yohan gains incredible clarity of perception, said to be on par with Superman allowing him to track fast-moving objects with ease and even predict the subsequent movements of those objects. Additionally it grants him exceptional analytical powers, allowing him to instinctively pick up on various visual clues with little difficulty. Not only is he able to use this ability to instantly master any technique after seeing it once but his movements alone is able to nullify the combined effects of the Flower•Bird•Wind•Moon, a technique that is actually composed of four separate fighting techniques derived from natural phenomenon connected with the name.
Yohan's fighting abilities are said to be incredible as well, as one of the most powerful characters in the series, he is capable of easily fighting against both Ranma and Kazuki simultaneously utterly outmatching outclassing, and overpowering them during their fight. His ultimate technique, using string projectiles in shape of origami cranes, is able to render explosions and is almost impossible to evade due to the sheer number of the cranes.
Finally despite his tremendous power Yohan cannot be easily detected due to his incredible control over that power. It’s true that a person’s aura shows how strong their spiritual energy is. But it also shows how their control over their aura isn’t fully mature yet. Yohan is able to prevent his spiritual energy from leaking out of his body eliminating wasteful energy spending and completely hiding his presence.