Earlier when Seth had fed on Amelia, he had been in a haste to quickly get her blood and focus on the attacking Diana, but right now the only thing he had to focus on was the pinned woman below him.
"ahhhhh" Diana moaned as Seth bit her neck, her actions surprising him but doing nothing to stop him from feeding, hearing her moans only made Seth hold her harder as he greedily began sucking her blood.
Just like with Amelia, Seth fed on Diana without care, unaware of the special energy he sucked out of her, he had his eyes closed as he enjoyed the delicacy flowing into his mouth, it tasted so sweet that he felt addicted, Diana's moans only serving to increase his appetite.