Yerbol had thought that his Masters at the Academy put him through the proverbial wringer until their first day of training with Renso. He warned them, of course, before they had begun early that morning. Training would be rigorous, intensive, like nothing else you two had ever experienced. Acknowledging what Renso said was extremely different than actually experiencing the conditioning runs he had them doing, sprinting through the pitch black tombs with nothing but their senses to guide every footfall, every subtle stride that avoided a fallen skeleton or skittering creature that called this morbid monument their home. Every fall was punctuated with a correction of mechanics("Feet need to be striding in FRONT, not the side!" "Focus on the environmental cues! Everything is obvious if you use that brain of yours!"), the falls not limited to just their physical conditioning runs; they were also instructed in saber techniques and Force abilities that gave them both new ways to tackle the "growing darkness" that Renso continually mentioned in their training. The first couple of days were aggravating due to Renso's constant correction on Yerbol's form, which the latter thought was serving him just fine thank you very much, but Renso was awfully good at convincing the both of them to listen. Unfortunately for Ari that meant lightning shocks, to which Yerbol protested vehemently. Those protests, however, were quickly silenced when a few moments after the punishment Aria swept through the air, slicing through the manufactured targets that Renso conjured(they were in the form of obsidian colored spheres that dissipated when struck) with a kind of fluid aggressiveness that Renso had been preaching to her. His partner was growing more powerful by the day and so was he. His defensive forms were sharpened by Renso, refined to cover glaring weaknesses that he would have never noticed until Renso pointed them out by striking him with gusts of Force energy that almost made his lungs shrivel into nothingness. Their combat and physical training culminated every day in application, Renso pitting them against Force projections of faceless forms armed with quarterstaffs that HURT when they connected. After the first week of fighting those, Renso pitted the duo against each other in a sparring match that he said was necessary due to their "opposing styles. It would be good for the both of you to know how to effectively deal with foes that are diametrically opposite from yours." It was odd to have Aria opposing him, even if they were just sparring, but her competitiveness and their mutual desire to refine their skills helped him set aside his reluctance. 
"Not made of glass, right, honey?" Yerbol said teasingly when they began, their sparring matches proving that his partner was indeed a ferocious combatant even against her lover(he KNEW she was skilled, but having her knock him to the ground with a leg sweep followed by a ferocious leg scissors reinforced the idea). 

Combat was paired with the teachings of the Sith, which was a breath of fresh air for the Champion, hanging to the words of Renso for dear life. The philosophy of Balance, of harmonizing the Force and maintaining control while knowing when to unleash it's full power was everything Yerbol had craved to hear on Tython. Before falling asleep on their ship with Ari nestled against him, he would pore over the few texts Renso had preserved from Quensu, attempting to absorb all the information presented. They were to be teachers, after all, arbiters of a new era that would hopefully establish the kind of unifying harmony that was only a pipedream just a few months before. It was thrilling, but sobering as well; Renso made sure to remind them that the Xiis were out there, hungering for the power that they believed Renso stole from them through his zealous idealism. It was on the fourteenth day that the Xiis became his sole focus, barely able to rise from his meditation when the duo walked in the chamber when he breathed out: 
"They are growing in number." 
"The Xiis?" They came close to him, helping him straighten up as he nodded.
"I could feel those who awoke leave this part of the galaxy. They were silent, but just now...now there are more." He walked shakily to the exit of the chamber. 
"They will stop at nothing to devour the galaxy." He motioned for them to follow, hanging a right at the exit of the chamber and descending further into the tombs, a path familiar now to the duo. 
"Chaos is their primary focus, to destabilize. With your government already in a fragile state, they will take advantage of this." Sighing as he continued:
"Their very presence constitutes a threat to the existence of the Force. You must stop them." 
"There are only a few left though...with our numbers-"
"It's not about the strength of your forces, Yerbol!" The Master snapped knowingly as they curved left, heading slightly upward, the air hanging damp and heavy. 
"Has anything sunk in that I taught you? Strength of number is less important than strength of will. These creatures will outlast any large contingent of forces by their tenacity and power. Throwing wave after wave of soldiers against them will do nothing but feed their bloodlust, which will only make them grow stronger." The path was now illuminated with flickering blue flames emanating from scones on both sides of the hallway, which abruptly ended a few feet later with nothing but a square pedestal. 
"This will be my last gift to you both." He curtly observed as the pedestal sunk into the floor, gently clicking in place. The once solid wall facing them opened up in two spots at shoulder height, serving as hiding places for two very special objects. 
"Two halves of this crystal, when embedded in separate lightsabers, create an electric field around the blade. Focus hard enough and you can project bolts of lightning every time you swing. Careful not to injure friendly parties, though." He finished with a smirk, handing Aria the two glowing halves before retrieving a silver hilt embossed with navy blue circles across the surface. 
"Your strength and power is too blunted by a single saber. This double bladed saber will serve you well in the times to come." Yerbol took the heavier hilt with caution, examining the etched grooves right as Renso collapsed to both knees, jaw slack. He pushed the duo away when they tried to help, admonishing them:
"Finally...pea...c..e.." He groaned, hands on the ground.
"Th...e..f...o..c...e..balanc..." His weakened body collapsed to the cold tomb floor. 

____

"YUN!" Her neck craned towards her brothers, their arms laden with the bodies of those in front of the ruined temple. She cackled gleefully, bounding towards their kills, grazing her fingers over the flesh with eager anticipation. 
"Sleep has only made us stronger, has it not?!" She jubilantly proclaimed, eyes cast towards the entrance, moving to the high ceilings, memories flooding her mind. The torturous needles, the countless beatings, the indoctrination that this place stood for...she swore they would pay; and although the last of their kind is gone in this strange new world, there was still opposition. Blood sport. Bodies to eviscerate, humans to feed on, a government to topple. They would re-establish their dominance, starting with this decrepit excuse of a world. Such cowardice! Shuddering in alleyways, shooting each other with blasters from afar, pathetic groups attempting to impose themselves on even weaker parties. 

Yes. This would be the perfect starting point. 

"Dispose of these?" One brother asked, sharpened teeth chattering. 
"For now, let them be a warning." She ran a hand down his muscular chest, tongue running over her lips. 
"The fat slugs above need tending to."
"Slugs!" Another repeated. 
"Patience, brother." Her hands ran over the form in front of her, tracing down his lower back. He would do as her first in a LONG time. 
"We will strike when our sisters have returned with favorable news." 
"When?"
"Soon. Very soon."