The Vampire Lord

The blood is the life. A simple truth, twisted and engorged by vampirism. And when the blood runs in torrents, and the cup of life runneth over, how perverted can that truth become?

An answer lies in the vampire lord. When a vampire is glutted on a hundred or more lives, its paranormal metabolism kicks into overdrive. Night itself is reified within the vampire's body as the blood is converted first into the typical profane energy which saturates the vampire's body and soul and makes it what it is. When the body is at capacity, and yet more and more sustenance presents itself, the vampiric mind, loathe to abandon any of its spoils, automatically begins to use the excess energy to weave tangible shadows that flow through the veins of the burgeoning lord. Their blood darkens, eventually being replaced entirely with dense, fluid midnight. This state, technically speaking, is not yet a lord, however, for it has yet to undergo the umbral metamorphosis which converts every cell in the vampire's body to living darkness.

While the vampire lord is more than adept at appearing human, its entire physicality it made up of evil made manifest. However, this form retains the accelerated metabolism initially kick-started by the vampire's feeding frenzy, and has roughly ten times the appetite it had before metamorphosis. Often, clever lords will sire subordinate vampires, send them each to feed on multiple humans, then drink their enriched blood.

Umbral Metamorphosis
When a vampire's blood is fully converted to umbraplasm, the body is ready to undergo what is known as the Umbral Metamorphosis. The vampire will seek out a suitable location to hibernate for a week, usually a well-guarded crypt deep in the earth. During its metamorphosis, it is wrapped in a chrysalis of umbraplasm, drawn out from the veins to wrap around the body. First it forms a thin sheet over the vampire's body, which sinks into the skin, fusing with it. Then, the remaining mass of umbraplasm begins to transpose itself with the vampire's flesh, slowly digesting itself. Eventually, it will have replaced every (important) part of the vampire. The only internal organs remaining are a swollen, onyx heart, almost crystalline in appearance, and the feeding apparatus. Unlike a stomach, the vampire lord's esophagus simply leads directly to its body cavity, passing briefly through something similar to a filter, which converts blood into the more energy dense umbraplasm. The soul of any killed and eaten by the vampire lord is destroyed and consumed, being completely digested within sixty hours. [Check when the lord is destroyed. -20% chance, +2% per hour passed, that the soul has been digested. (The soul is never digested within the first ten hours, making these a guarantee for any hoping to free or resurrect the soul of the victim)]
Similarly, their thralls are capable of carrying souls to their lord, although they cannot digest them. This prevents resurrection, but at least offers greater hope to their savior's efforts, as a thrall is much easier to kill, and the only time limit is until they return to their master, and, depending on their orders, that could be days or even weeks.