In Saint saint seiya, why can only Saint Martin hurt Hades?

In the cartoon "Saint saint seiya", Hades can be said to be Athena's most powerful opponent. The struggle between them not only lasted from the mythical era to the present, but also was very tragic every time. In the last jihad, saint seiya, a saint of Pure Land, achieved the ultimate eighth sense. Wearing sacred clothes, she found Hades, and with the belief of protecting the peace of the earth, she hurt Hades' body with great strength. After that, the injured Hades seemed to remember something, saying that he met this saint more than 200 years ago, and saint seiya, also a saint of Sagittarius, stabbed himself.

In the jihad more than 200 years ago, Hades chose the wandering painter Aaron as his birth body. On a snowy winter day, Aaron came to a shabby house alone, trying to escape the bad weather. At the same time, a wandering teenager named Tianma also came to this nest, trying to stay here for the night to avoid the wind and snow.

The two tramps soon chatted, and the kind Aaron completely believed in Tianma, burned his precious books, and raised the temperature of the room to a higher level, so that Tianma could feel the warmth. But what I didn't expect was that in the middle of the night, Aaron was awakened by the cold and found that the once wandering teenager Tianma was gone.

It turned out that Tianma was a thief, and the escaped Tianma was caught by a man named Water Mirror. Originally, the water mirror wanted to kill Tianma, but Bruto begged to save Tianma's life. Aaron eventually became Hades, while Tianma became a saint, and it was Tianma's attack that finally stabbed Hades. It can be said that it is a coincidence.