Hylden

The hylden were one of the 3 races of Nosgoth, along with the ancients and the humans.

Somehow, by rejecting the elder god, the hylden managed to make themselves exempt from the wheel of fate and thus were immortal. They had green skin, leathery wings and crests on their heads, as opposed to the ancients feathered wings, blue skin and hair.

Probably prompted by the elder god himself (due, most likely, to his anger at their avoidance of the wheel), the ancients tried to persuade the hylden to join them in his worship. The hylden refused and the ancients soon went to war with them (again, probably at the promting of their god).

The two races were evenly matched as they battled in the skies over Nosgoth and both races attempted to create a weapon capable of winning the war instantly. The hylden weapon was known as the device which channelled the power of a being they had captured known as the Mass, which could kill creatures with a thought. the Builder built it underground in the southwest of Nosgoth but he lacked something that could feed the Mass with the life energy it needed to project it's deadly thoughts. Before the problem could be solved, the ancients had created the pillars of Nosgoth, their weapon to end the war. The pillars forced the hylden into the demon dimension, but not before the blood curse could be cast on the entire ancient species which cursed them all with vampirism. Only the Seer managed to stay in Nosgoth.

While in the demon dimension, a few powerful hylden learned how to send their spirits back into Nosgoth to possess its creatures, as well as view the Timestream of that realm. One of these powerful hylden, who seemed to call himself Hash'ak'gik managed to force his disembodied spirit through the binding caused by the pillars when Kain refused to sacrifice himself to them in 0 A.B.O. He possessed the recently resurrected Janos Audron and defeated his only obstacle, Raziel before escaping. He used Janos to reopen a dimensional gate which he used to bring his body through into Nosgoth. He then fed Janos to the Device who, as an immortal, was a perfect being to start the completion of the weapon. Abandoning Janos, he seems to have then attempted to create a causality loop by possessing Mortanius, decades before who he used to murder Ariel, which created Kain who corrupted the pillars in the way which allowed him to break through into Nosgoth in the first place.

He possessed a human and used the fear that the population of Meridian (the city which was built upon the site of the device by the humans) felt to re-create the Sarafan. With his own personal army of humans, Hash'ak'gik defeated Kain, completed the and began using the dimensional gate which he brought his body back with to allow a slow trickle of hylden back into Nosgoth. Unfortunately, Kain destroyed the gate, sending all of the returned hylden back to the demon dimension.