At the key moment, Bai Yijian stepped in to crush the beams of light that had materialized from the Divine Decree! Su Yu was not surprised by his interference.
After all, it would have been questionable if he had looked on heartlessly as his son was killed by someone else! What really surprised him was Bai Yijian's Divine Decree.
Crushing the Divine Decree with his bare hands was not something any person with a strong cultivation could manage. As such, he must have had a very high level of Divine Decree to be able to accomplish such a feat!
Bai Yijian's Divine Decree was most likely above the divine-grade. As such, Su Yu wondered if Bai Yijian had achieved Pure Divine Decree level, like himself.