So Kas the Destroyer. In fact no official artwork beside the one in domain of dread exist about Kas. The Ulraunt's Guide to the Planes : Shadowfell (a Dm guild book of incredible quality) depict him in a too classical way. After all he survived, some scars can't be magicly healed. It's why i choosed to make a pic of him not in a "classical and gothic way". And now beware of the wall of text ^^.
More than one millenium ago, the king sitting on the throne of Tovag was know as Kas of Tycheron. During his lifetime he would be know by many other names, The Terrible, The Destroyer, The Bloody Handed, The Betrayer and The Hateful. Today he’s The Immortal.
In life he was know for his skill and might as he was feared for his evil and vilainy. As the chief lieutenant of Vecna, Kas effectivly ruled a vast empire governed through fear, tyranny and terror. After years of loyal servitude from Kas, Vecna presentend him with an extremely powerful magical sword. Created by Vecna himself, this sword will become a symbol of defeat and pain on all battelfields and soon been know as the « Sword of Kass » and made an already legendary warrior into an archetype of evil.
In time, however, the magical blade began to take a toll on its master. It took some of the worst side of Vecna’s personnality during its creation and wanted to see its weilder sit on Vecna’s throne. The sword pushed Kas to turn on his master, determined to usurp the throne for himself.
The battle between Kas and Vecna was tremendous, laying waste in the kingdom until the civil war reached the Black Tower. The final confrontation took place at its peak. No one know what happened during the confrontation, no living or undead witness survived it and every divination or attempt to communicate with souls present at this time always fail. But the result was catastrophic, the black tower and everyone in and around it died in the magical explosion that put an end to the conflict and, apprently, destroying both combattants.
Some sages claim it was during this final battle that Kas severed Vecna’s left hand and left eye but nothing is sure.
No one know how or why but Kas survived and was brought by vecna’s faithful servants to its citadel in the quasielemental plane of ash. They waited for their master to return in order to judge the betrayer. Years, decades and centuries passed without Vecna coming back. Its servants fought between themselves for petty reasons and forgot Kas in his cell. During his confinement, the mighty Kas changed… As the negative energies of the citadel took their toll on his body, he gradually became a vampire. In addition his love for conquest and battle became a hunger for death and destruction. No longer he was the Betrayer, now he would become the Destroyer.
After centuries of imprisonment, Kas knew that something was going weird. The citadel was full of sound of fighting and his hightened senses were able to discern the scent of blood and smoke. Unknow to him or his jailors, it took Vecna centuries to put in motion a plan to conquer all Oerth and it failed, Vecna was defeated, his phylactery destroyed and his soul nowhere to be found. After centuries of conspiracies and resentment, Vecna’s servant unleashed a full civil war against each others. And so, Kas was free…
[Dread Possibility] No record exist describing the timeline of Kas’s jail period. No one know how he was abble to survive this long without any magical aid and not even the servants of Vecna left after the fights are able to give any reliable way to explain how he became a vampire. If it was the energies of Cavitus, why other motals, above all magical studients extending their life, didn’t and don’t undergo the same transformation. Some speak about a pact made with a dark entity, others say a traitor in their ranks helped him but no answer is likely to provide a definitve explaination to the simple fact that Kas survived and grew in power and hate. No one is even able to answer how he obtained the Mask of Kas that is now part of his regalia today.
Lot of questions are left unanswered about Kas early life and imprisonement but he is perhaps the only one to know the truth. More is know about his time as the darklord of Tovag.
He waged war against his foe as Vecna reappeared as Cavitus’s darklord and both were stuck into an eternal war. Kas didn’t understood at this time what power holds him in place or how he came to be here but he found a meaning in his existence. This statu quo didn’t lasted long since Vecna managed to set a trap to lure Iuz the Mad into his fortress of Cavitus and absorb his divine energy.
Kas launched his final assault again the fortress, using Iuz’s armies to push inside the throne room and kill his nemesis. Iuz falled into the trap set by Vecna and his death resulted in a magical explosion that saw, again, everyone dead, or worse, inside the fortress.
Kas didn’t survived this time nor he was done for and for countless years, all that remained of him was a vestige, fragments of a soul lost outside space and time. Even Kas doesn’t remember a lot of thing occuring during this time, he compare his memory of this period as a miror broken in countless tiny pieces. Kas never speak to anyone about this time or how he managed to come back to « life », it’s one of the biggest mystery about him today. The strangest part is his bloodlust seem to be diminished, he seems more clever, calculating his every move and his strategies and political moves are way more subtles, sharps and efficients but always bring unexpected results. Even against all odds, he manage to win a battle, on a field or in his throne room.
Sometime it’s like he’s somewhere else, lost in his memories, looking at the misty border as he would be able to listen and understand peoples who aren’t even there. This trouble the few who knew him before his defeat in the cavitus citadel. Kas changed, he’s more powerful than ever but before his soldiers followed him by fear, now its admiration even adoration for lot of his officers. Tales about his history are told everywhere in the land of the Burning Peaks, how he managed to survive everything throwed at him and thrived each time. Stories abound about how Kas seems to speak to the mist, to bend it to his iron will and how he was able to leave it to recruit his more powerful allies in the War for the Stone.
[Dread Possibility] Even unknow by Vecna, the god of secrets, Kass was a dark power when he was a vestige, he was among them and remember some events from this time. He know something older and sinister lurke behind them. They use the mist and its power but didn’t created it. Kass don’t know what kind of creature can create a crystal sphere, destroy all exits and move it into the deep etheral but he find the simple idea of such tremendous power terrifying.
Or/And, as in the Ulraunt's Guide to the Planes : Shadowfell, soldiers and officers members of the Kass army are making shrines devoted to him, praying him for coming back alive and have a glorious death if not and, unknow the Kass himself, he’s beginning to acquire the powers of a demigod. He’s earing some of their payers and it make him remember what is was to simply be alive.
published in 1989. So to create a crystal sphere, move it from plane to plane and closing it is, imo, waaay more terrifying than just the explanation of the shadowfell. It lead players to ask questions about the power and the motivations of the beings behind the misty realms. It's why i found the "canon" explanation of "Lords of Necropolis" weird. Even Acererak, the most powerful demilich in D&d can't even scratch the level of power nedded to create all of this.
