As a powerhouse in the Netherworld, only next to Ksitigarbha, it's a pity that Yama Heavenly Son is such a figure, because he had the greatest hope in the Netherworld of advancing to the True Martial Realm.
For decades, the Netherworld had been oppressed by the Heavenly Court. What they lacked was just foundation. Had Yama Heavenly Son not encountered mishaps back then, it is estimated he would have already advanced to the True Martial Realm by now. If the Netherworld had two True Martial powerhouses, they wouldn't appear so weak before the Heavenly Court.
Hence, when Hou Tu heard that Su Xin could compensate for Yama Heavenly Son's deficiencies in his Cultivation Technique, she was also very excited.
Naturally, Su Xin sought out Yama Heavenly Son this time also because he valued Yama Heavenly Son's current strength.
It could be said that among the martial artists in the Sun God Realm in Jianghu nowadays, Yama Heavenly Son was the strongest one.