In his haste, Tang San tried to use Divine Slaughter's Domain to dispel the chill, but for some reason, he simply could not activate it properly. This was the "aftereffect" Slaughter City had left on him. Though Tang San had lived for twenty years, he had never actually experienced a real battle.
In the original story, before the age of fifteen, Tang San's only real combat experience, aside from that encounter with Shi Nian and facing Spirit Hall's assassination attempt, had primarily been accumulated in Slaughter City. But Mo Lin had not only dealt with Shi Nian for Tang San and helped him avoid Spirit Hall's interception, he had even deliberately arranged things so that Tang San encountered no battles in Slaughter City apart from those in the Hell Slaughter Arena.
Already lacking sufficient genuine combat experience, Tang San had then spent another year in this "peaceful" noble academy. Now, when faced with a sudden battle, he simply could not immediately gain full control of his body or properly mobilize and use his Soul Power and domain. He needed time.
What was more, the icy aura Mo Lin had unleashed came from the Ice Dragon King's left arm. Though it was not at its peak, and though Mo Lin had deliberately restrained it, Tang San could still clearly sense the newcomer's strength. The imposing presence mixed into the cold brought immense pressure—pressure far beyond anything any opponent Tang San had faced before could have produced.
Nothing showed on Tang San's face, but the tremendous pressure had left him more flustered than ever before, making all of the above even harder for him to accomplish.
Still, Tang San was a Soul King. Even if he could not stay prepared to counterattack at every moment, he could at least keep the cold