Before he had mutated, his strength was already considerable. Although in the end he had mobilized the mysterious power within him, for Jia Yan, the ability to fend off Strong Ones like Pai Lan and escape to the perimeter of the passage under previous circumstances was already an incredibly terrifying miracle. After all, his strength at that time was only at the Middle Starry Sky Period.
The largest contribution to this had been his Bluish Defense. However, merely having Bluish Defense was insufficient; after all, whether it was Pai Lan or his subordinates, they all seemed to possess the ability to break through the Bluish Defense. At that time, Jia Yan also relied on his combat experience and intelligence to make what seemed like a miraculous escape happen. You must understand, the combat abilities of the Strong Ones aren't that straightforward; that Jia Yan could escape from their clutches was truly a significant miracle.
Of course, all this had already passed.