After the two sisters had apologized to him, they retracted their pressure and immediately Nial felt relieved.
What he hadn't realized until now was the factor that not only his senses had improved, giving him advantages, but that also the presence, aura and intent of others were clearly perceptible to him.
As such, Nial sensed the anger and suffocating pressure released by Kira and Mara which was ten times more intense than what he had felt being around anyone else.
Thus, they were slightly baffled by his reaction and relieved once they retracted their inadvertently released pressure.
Yet, after Nial had begun explaining everything, stating that his senses and physique had been enhanced through the Curse he bound to his mana core, they were slowly starting to comprehend the big picture.