Took me some time but I hope it's worth it! 
Jester: I was under the impression that this was during the Jedi Civil War. That's the timeframe for the whole RPG has been in for some time (since we last restarted). It's why Revan, the Jedi Exile, and the war itself are intertwined in my Force vampire plot. [I'll wait to write my character's part until we figure this out.]
Also, Mortis (a.k.a. the Vampire King) does not have a weakness. He's like the ultimate bad guy of the ultimate bad guys you know? The only reason the vampires nearly went extinct was because the Elders started hunting them down one by one. Eventually Mortis grew tired of their game and eradicated the entire species.
On another note, you -as a vampire yourself- are instinctively drawn to Mortis; your desire is to serve him. It's in your very nature, etched into your bones. This isn't like the Sith were the underling(s) despises the "Master" or eventually tries to off him. Force vampires are fiercely loyal to one who's proven himself as their King.
Only purebreds can hold the title and even then only the strongest of them can claim. There's no use in anyone trying to take it for themselves seeing as there are very few purebreds and none of them match Mortis's power. The Vampire King cannot relinquish his title to another, however, should the Vampire King die the title is immediately passed to the strongest remaining purebred.
If no purebreds remain to carry it the title will remain void until another is born. [Man that was longer than I thought it would be. I get carried away sometimes.
]
George: Fixed the error.
For the monster voice link (not the breathing, the actual voice) given below: 2:09 to about 2:13 is how I want the being's voice to sound. Real short I know but it's the best I could do. Not a lot of options but at least it gives you an idea. ^_^
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Riordan does not turn to them, his gaze remaining transfixed on the stairway descending into dim darkness as if it were something more. "I cannot say for certain," he replies to Mat's question, "but I... I cannot ignore it," he adds darkly.
Shouten Yaiba's flames dim, the sword voicing his uncertainty. My Lord... is such a risk wise? Whatever lurks within those depths... I fear I cannot help you defeat; I do not sense it as you do. I will be unable to harness your power and as such it will be of little use. My blade will not find the heart in this darkness...
Riordan waves his hand, uncaring. "I cannot ignore this, Shouten Yaiba. Something waits for me; calls me. I must go. If you cannot utilize my power then bestow it upon me; all of it. I shall no longer burden you."
My... my Lord?! Shouten Yaiba questions Riordan's sanity, beyond shocked. I... your body... should I cease my efforts to control your power and unleash it upon you... I cannot guarantee you would survive! You are still human...
"Yes. I am well aware of that fact," Riordan reconsiders. "Still... such a desperate act may be necessary... if only as a last resort." He steels himself. "Know my will, Shouten Yaiba," he addresses the blade cooly. "When the time comes I do not expect hesitation."
The sword is considerably defiant to the idea but he cannot deny Riordan's wish. Yes, my Lord, he agrees submissively.
The noble throws Leina and Mat a careless glance as if unaware of the woman's ignited lightsaber and both individual's heightening suspicion. Hmmm... he was acting rather odd wasn't he? The dark gleam in his eyes suddenly fades and he appears to regain control of himself once more.
"We must move swiftly," he speaks, his voice thick with icy authority only a noble could produce. "I do not wish to spend anymore time in this cursed place than needed but I must deal with whatever lies beneath this Temple. I shall not allow it to escape."
Without checking back to see whether or not the two Jedi follow him, Riordan begins his descent down the stairs. Of course the two have little choice in the matter it seems and follow, though somewhat reluctantly. The stairway which leads to the lower level of the temple curves, wrapping around a rather large waterfall which flows far into what appears to be a bottomless pit.
Riordan is careful to watch his step on the slippery stones, his grip of Shouten Yaiba's handle as merciless as ever; unrelenting and ready for whatever awaited him. The stairs flatten and straighten out to form a wide hallway which leads into an open area, the edges of the gray plane falling down into the same depths and darkness as the waterfall.
Only two doors greet the trio on this bottom level of the Temple. The door directly in front of them is simple but strangely a fire burns in the torch placement on the wall above it... as if someone had been there recently. The door to the left is slightly smaller but a massive skull-like crest adorned with four animalistic horns rests above it, two fires blazing atop the small columns on either side of the door itself.
Riordan remains motionless, unsure which door to test first and whether it would be wise to open himself so gallantly. Suddenly the door in front of him opens, darkness seeping out onto the fire lit floor, consuming whatever light it finds. Riordan raises Shouten Yaiba, daring anything to leap form the shadows to devour him.
However, when the noble catches the fleeting vision of the woman once more the man throws away his guard and rushes in, Leina and Mat on his heels. The room closely resembles the desolate place where they encountered the Vashan Abyssian though a deep, haunting blue light dances dimly throughout the room.
Riordan remains unconcerned, his focus on the ghostly phantom of the woman escaping his grasp. He eventually loses sight of her in the darkness and groans in frustration.
"Damn it! Where is she?! Where did she go?!"
The noble suddenly realizes he is unable to move, turning his head to find Leina and Mat in the same predicament. He curses violently, tugging at invisible restraints. His struggles immediately cease, however, his body tensing as the cold breath at the back of his neck sends shivers down his spine.
Leina and Mat can do nothing but stare at the large cloaked being which materializes from the shadows behind Riordan, the sound of its breathing haunting their minds with vicious images of what lay beneath. Though the lighting in the room is poor the inhumanely bent legs of the figure beneath protrude from the cloak, glistening whitened fur clinging to purplish grey skin.
An arm moves from within the cloak, a long, clawed finger trailing down from Riordan's ear to his shoulder, slitting the flesh of his neck open, bloody slowly seeping out. The noble groans softly, his attempts to escape resuming.
"What is this? What is going on?!" he demands as if he expected to be answered.
The figure behind him presses it's tongue to the cut on Riordan's neck, moving upwards to lick away the blood, its salvia burning the man's skin. "Rgalom," it answers, though none of them are sure what it says. The violently deep, animalistic voice seemed to be communicating more with mutilated growls than actual words.
"Juo'vigyaz peje agba'son," it continues slowly, demonic voices eerily echoing the being's own words around them. "Han ku'eka majaknak fu'gond en."
Riordan suddenly gasps, his eyes widening, the breath in his lungs hitching as the figure moves away and his body is crushed by an unseen force. The noble's back is forcefully arched beyond humanly possible measures, the man crying out in unbearable pain as the sound of bones breaking echoes in the empty room. Riordan's body goes limp, whatever holding the noble in place now the only thing keeping him on his feet.
The cloaked being fades into the shadows only to emerge behind Mat. It grabs him under his chin, forcing him to look towards the ceiling. The Jedi's eyes stray to the side, catching the faintest glimpse of haunting red eyes hidden within the darkness of the hood of the cloak. Pain shoots through his body as numerous sharp teeth penetrate the tender flesh at the crook of his neck.
The figure moves away, treating Leina to the same punishment. After a while they can no longer keep their eyes open, pain throbbing through their bodies as everything fades to black. The demonic voices echo in their minds as they cling to the last traces of consciousness.
"Welcome... to Despair..."
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Well... now we know that it's not Shouten Yaiba's power the blade is lending the noble. In fact it's the noble's own. As I said before Force vampires share their power with a spirit which is bound to a weapon. Otherwise the power emanating from their own bodies would crush them. So Riordan's more powerful than he pretends to be... hmmm... 
Ah, the lower level of the Temple. Despair and Sanctuary are the only two rooms here. And our characters have just fallen into a little snare within Despair.
You see within despair lies a being/figure which traps people in a very unique way: with the Force. The poison in its salvia then works to augmenting the smallest amount of pain to unbearable levels, sending the poor souls it happens to catch into a coma.
While trapped, the being's victims experiecnes moments of their lives in extreme detail, able to feel everything and thus not aware that are currently not existing in reality. Usually the victim is forced to relive events in which they failed miserably over and over again until they fall into despair. Where such failures do not exist, events are twisted within the mind and great achievements are destroyed to become grave failures.
You're fixing to learn a lot about Riordan and Kain's past like how and why Riordan became a noble; why Kain gave into the curse; maybe how they met Slade; etc. This is gonna be good. ^_^ Leina and Mat are gonna be unconscious as well until I work them out somehow so feel free to have events of their past come back to haunt them. Like if they save some people or something its twisted so that they didn't get there in time and they were all mercilessly slaughtered.
Feel free to drag it out because Riordan's past is filled with hardships so it'll take me a few long posts like this one I think.