You're Not A World Beast.

Vampires have their own advantages and they have their own domain. He just needs to spread his type of domain. Since his domain is him and he is his domain, the activation of his domain led to another growth spurt. 

Blood spurted out from within him like a spring. But it didn't spread outwards to form a blood domain. It became his flesh which led to him getting bigger and bigger. Soon he grew to become 3,000 meters in height. That still isn't the end. He is still growing thanks to the infinite supply of blood power from the Supreme of Carnage. 

He roared with pride. "Behold the might of a Primogenitor. Look at the immensity of my existence and feel insignificant."

Ragnarok's eye twitched. "I can admit that I am a little jealous."