Of course, it was because of the darkness Sakim had stolen previously that caused the entire surroundings to suddenly turned dark. When he used it, it was as if some kind of especial barrier had appeared and separated the darkness from the rays of the sun where it was helpless to pierce through this darkness.
This caught the two women off guard. And Sakim didn't waste this opportunity to approach the crimson-haired woman. That said, as the distance was being calculated in his mind, he managed to grab the neck of that woman extremely easily.
Sakim didn't show any mercy as he didn't give any opportunity for that crimson-haired woman to retaliate. Just after he grabbed her neck, he quickly stole her HP making her suffer her doom.
arrogance = stupidity