After a moment, he saw that the youth had made a mistake. Taking this chance, he immediately attacked towards the throat again, aiming to pierce the throat and end his life.
Just as the dagger was approaching the youth's throat, his movements suddenly sped up, showing no signs of the initial staggering. He caught the arm that was holding the dagger as he twisted it to the side, evading the blow.
Immediately after that, using all the strength in his hands, he pulled viper in. Before viper could react, he was kneed on the chest. Reflexively, he tried pulling back his arm.
But, in that spar of a moment, the youth had managed to pry the dagger from his hand. As viper staggered backwards, the youth suddenly jumped forward and pierced the dagger through viper's left chest, directly piercing his heart.