If no one posts in 20 minutes, I'll edit this post with segment 2.
"Anything else you've ever felt? Anything... aetherial?" Illustrus was intrigued.
Heimdall remembered back to morning. "Yes... I... I think I once used my mind to... repair myself, sort of. I concentrated, and I was no longer tired. Blue waves flew off of my skin for a second before I absorbed them and felt energy flow into my body."
Illustrus's eyes flew open. "When was this?"
"Just this morning."
With a fire in his eyes, Illustrus stood up. "If..."
In a motion so fast Heimdall had no time to counter it, Illustrus had unsheathed his sword, glowing with sigils, and had swung it at Heimdall's right side. Heimdall instinctively protected his mind from the pain he knew would come and closed his eyes. However, he felt no pain. Warily, he opened his eyes. Nothing had changed. Illustrus was still standing, an expression of sheer wonder on his face. Behind him, Veneficus also stood, dumbstruck and slack-jawed. Heimdall stared at Illustrus's sword, which was sticking straight into Heimdall's stomach.
But Heimdall was different. His body was like a pane of glass with only the contour showing. He stared at his hand and chest. They were devoid of color, and he could see straight through the woven carpet at his feet through his clear body. My god.
And then, Illustrus had pulled his blade away from Heimdall, and Heimdall regained his normal, corporeal form. They sat down once again. "What?" Heimdall said, panicked. "What just happened?"
"Q... Quint... Quintessence..." said Illustrus. Heimdall had never seen him so shaken. "A Quintessence spell."
"Quintessence?" Heimdall had only heard of that once or twice. "Isn't that... a potion that makes you... immortal for a period of time?"
"Yes," explained Veneficus. "But the potion itself is extremely rare. Immortals like Illustrus are born with the ability to be 'immortal'; in fact, this is really the ability to phase out into a dimension parallel to ours. For Immortals, this ability is active; they must will themselves to phase out into the alternate dimension. For the select few who have Quintessence potions, the effect is automatic. While one is in the phase dimension, one cannot be hurt or harmed by the physical world... at all. Quintessence also serves to rejuvenate and revive."
"But I don't have a Quintessence potion!" said Heimdall. "How? How did I do this?"
"Again," said Illustrus, "You have innate powers of Aether. You have demonstrated this twice. You... are unique. I've never seen anyone like you. You should experiment with your powers. Try to cast Quintessence on someone else. Try to use Thunderbolt again. Experiment, like I do. You're the only one who can unlock you're own powers."
Before he knew it, Heimdall was thanked out of the barracks. as he pushed and shoved his way back to the relatively calm streets of Umbrios, Illustrus's words echoed in his ears. You're the only one who can unlock you're own powers. They told me what these powers were. Aether. And it definitely has something to do with my shard... but I have to learn for myself. Experiment. I guess I'll start here. He noticed Orthon, the vampiric manservant, wandering in the streets.
"Hey, Orthon. Can you do me a favor?" said Heimdall.
"Eh," said Orthon. "I'm on my break. It better be simple."
"It is," said Heimdall. "Hit me."
Without a pause, Orthon said, "Don't mind if I do!" He pulled one fist back and swung it. It caught Heimdall square in the chest. Heimdall staggered backwards, bile rising to his throat. I guess my time limit is up. "That good?" said Orthon with a huge grin.
"Thanks," said Heimdall, walking away quickly.
"Pleasure's mine!" called Orthon. Heimdall strode quickly back to the citadel, clutching his upset stomach with more questions than answers.