Before the fall House Al'demar was known for it's affinity with the warp and it's psychic prowess. But that all changed with the fall, while all of the Eldar were rocked by the loss of their psychic powers, for the Al'demar it took more then just their psychic might, it took away their position in Commoragh, their power. Their houses powers dwindled, while frantically searching for some other means of power. Years passed on, and the House was considered a lesser house at best forgotten by their peers and potential enemies...
When Vect took control of Commoragh, House Al'demar was left untouched as it was no threat whatsoever and they quickly assumed the Kabal structure for fear of destruction, and they finally found their means of power after centuries of searching. For when Vect took control of Commoragh, he encouraged raiding to a degree the Noble houses had forbade, and House Al'demar changed forever. The Newly formed Kabal lacked a name, they lacked something that made them great until Sevran took control of the house leading raids that would shroud entire worlds in night causing fear, panic, and loss of everything on many a world, and from the screams of the Mon'Keigh they finally gained their name... The Nightsworn.
Uner Sevran's leadership the Kabal was regaining power and earning position within Commoragh their ancestral home ripe with slaves and wealth. Brokering deals with Craftworlders, creating Corsair fleets, and trading with Exodites all increased the Nightsworns power and connections, a chance for the Nightsworn to reach the upper echelons of Commoragh was once again in their grasp. But as seems the fate of the Al'demars they fell yeta gain. In fact they were betrayed. The Haemonculus Verix in their service had found patronage with a more "bennficial" doner the catch was to make sure the Nightsworn fell, and fall they did for Covenite and Kabalite alike attacked their Citadel and Sevran lead a mighty defence and repelled the invading forces, but that is when Verix made his move and killed the Archon... sparking rage in Sevran's son Rhvan he hunted down Verix but to no avail. Causing in the Nightsworn's fall once again, but also a fear.
After his father’s death, Rhivan developed an intense fear of his own death. But he couldn’t turn to the haemonculi for they’d betrayed his father… He needed to find another way to bring him back from death. He began to experiment with soulstones, twisting them and corrupting them, until something new was created. The Soulstone had absorbed his soul… well a portion of it, Rhivan wasn’t dead, but neither was he fully alive but it made him stronger, and now there was something new within his grasp. Something forbidden dancing in his mind.
Through experimentation with his new existence he discovered he could imbue others with his gift, by doing so their soul’s were tied to his, this transformation made the newly raised Undead with loyalty to him while still retaining intelligent thought. Though not all of his creations were capable of such as Rhivan was able to animate skeleton’s to his whims, and raise undead abominations to join his ranks...
I'm still working on the lore especially with the new Ynnari rules coming this way, I love how I was making a Necromancy based Kabal and now I have rules to go with it (Originally I was going to use Coven units converted to be Undead but now...)