I think the reasons are as follows. When Tomoka bravely said, "Don't sympathize with cannibals, they are just ugly monsters", Tanjiro retorted, "In order to avenge the slain and prevent more people from suffering, I will definitely cut the knife to the ghost's neck without mercy. But I won't trample on those who suffer from being ghosts, and I won't regret their actions, because ghosts used to be people and people like me. They are not ugly monsters, ghosts are empty creatures and poor creatures! As Tangiro said, ghosts used to be people, and most of them had an unknown painful experience. Who would give up human identity if they were not desperate for life?

Black Death Mou, one of the first chords of the Twelve Ghost Moon, is the strongest ghost under Ghost Dance. He easily defeated the black-striped Xiazhu without hesitation. It is recognized that the strongest rock pillar, together with the wind pillar and Zhu Xia, did not prevail. When he was a human being, his name was Jiguo Yansheng. He used to be one of the original swordsman, and he was also the strongest swordsman who cast a shadow without suffering.

He is the twin brother of Japanese call user Ji Guoyuanyi. During the Warring States period, Japan's class concept was very serious. As the male heir in the family, he is always inferior to his younger brother. No matter how hard he tries, no matter what, he is still far behind his talented brother. This feeling is very unpleasant. Living in the shadow of his younger brother every day, in order to surpass his younger brother, he became jealous and finally became a ghost. Sixty years later, Ji Guoyan Sheng, who has become one of the top figures, met his younger brother again. At this time, the fate of Yan Sheng, the successor to the country, has reached his twilight years. Yan Sheng was surprised that his brother, a striped swordsman, was still alive!

facing his once annoying itchy brother, Yan Sheng didn't feel any anger. When he was a man, he just wanted to kill his brother, but even though his strength was still the same as in his heyday, Yan Sheng cut off his arm before he drew his sword. Strong frustration seems to have crushed Yan Sheng's internal organs into a pile of meat sauce. He knew that when his brother swung his next knife, his head would fall to the ground, but his brother couldn't swing the next knife that had to be killed, so Yan Sheng stood and died. Maybe he knew from the beginning that he would take his own life. However, seeing his brother leave tears like this, he hesitated when wielding the knife. So I think this is why Black Death Mou became a ghost.