The Nephilim are born of Grigori after coupling with human men. The Grigori are forced to stay in the form of human women for two months (the gestation period for these creatures). These beasts are so linked to their mothers that any attempt to abort the fetus would result in the destruction of the Grigori. The birthing process is a long and painful one for the Watchers. Around the time of delivery, they seclude themselves in the deepest reaches of the wilderness. Their cries of agony shatter the night and make even the fiercest of Gods creatures cower.
The monstrosities born are unrivaled in their hideousness. There is no set prototype for these beasts. Few resemble anything even remotely humanoid. These creatures are far more primal. Some have tentacles, others horns. They are dark creatures, possessed of an unchecked evil.
Almost immediately, the Grigori flee, not out of fear but disgust for what they have conceived. The Nephilim are left to the night, to slither into the deepest shadows, to grow old and grow strong. Many of these creatures hide forever in the wilderness, feeding on the wild things by night. Some, however, manage to make it to civilization where they take refuge in empty warehouses and dark basements, feeding on the flesh of the children of clay.
Though they are creation's wildcards, there are a few cohesive aspects to all Nephilim. The longer they live, (their natural life span seems unlimited unless checked) the more they grow. The elder ones, those who survived the flood, are rumored to be taller than mountains. These creatures are said to bide their time at the bottom of the oceans, occasionally surfacing to swallow ships or ravage ports. Another assurance is that the older they get, the more powerful they become. The young ones are easily dispatched by even the lowest ranking angels. Those who have survived a century are usually strong enough to fend off Principalities. Those who have lived five hundred years or more can pose a threat to the Dominations. And the Seraphim themselves will not battle one of the Nephilim who has lived a millennium or more.
Because of their hideous appearance and, in some cases, their enormous size, the Nephilim have adapted powers of concealment and deception. Many, but not all, have the ability to contort and compress themselves, their huge mass filling a small area or spread throughout the inside of a wall. Some may even be capable of rendering themselves invisible to the naked eye. There are so many variations of their form and powers
that its difficult to make generalizations about their capabilities. The storyteller is encouraged to concoct any horror that suits his fancy and classify it as one of the Nephilim.
One fact is certain. There were many more of the Nephilim in years past. They gave rise to many of the mythological tales of monsters. but their war with the children of fire has taken its toll. Most were hunted down and destroyed by the middle of the 19th century. Only a few stragglers remain. Most are young and weak, but some of them (the old
ones) have power beyond imagining.