Shangtian was suffering insane amounts of damage from the Destruction Energy rampaging through his body. His Undying King Inheritance could barely keep up with his healing, because Destruction destroyed, not damaged.
The bloke was forced to literally recreate parts that had been destroyed only for them to be obliterated once again. He roared as he fell to his knees, feeling the power in his body leave him slowly.
Still, he knew he couldn't let it end like this, so he jumped forward with what little strength he could muster, wresting Draco's claw from his torso.
He then gripped the claw with both hands and used his strength to raised Draco into the air. Then, he smashed the Black Dragon into a ditch one side, then a ditch on the other, over and over again like some rampaging hulk.
When he tossed Draco aside, the guy rose from the ground clutching his head, his eyes spinning.
"Wha-what day is it?"