Kretos was surprised that his attack wasn't able to damage Sora's body. Even though he was sure that his sword had made contact with Sora's flesh.
'Amazing, I and all demons have great regenerative abilities but it's nothing this perverted. I cut this guy's arm off and it looks like nothing happened to him. I wonder what else can his body do? Does he have an undying body, or something similar to an everlasting body? This is getting even more exciting.'
Kretos got even more pumped up as he controlled even more weapons and attacked Sora with greater speed. He then started using some spells here and there to control Sora's movements. Every now and then as Sora's body was having difficulty in keeping up, he got hurt in multiple points in his body. Yet despite getting pierced by Kretos's blade, or being burnt by Kretos's spells, Sora remained unscathed throughout the battle.
For those of you wondering how long the demon lord Kretos arc is I will give an answer. This arc consists of fighting the demon lords, breaking the first four heroes, and the battle against the arrogant young dragon. Once those events are done we will head back to the current timeline and enter the next arc, Primordial Demons arc.