A/N: Welcome to my main and longest fic! This was actually started December 6th 2022 over on AO3, and this is the result of me porting it over here so it's on more than one site. This began post S4 and is canon divergent from S4 onward. The full fic description is in my bio for those curious.

Anyway, enjoy and feel free to comment! At the time I'm posting this here, the fic is still in progress and I love hearing people's thoughts whether a fic is finished or not. I'll be updating as I update on AO3 as well.

-BREAK-

Callum had been here before.

The ground beneath his feet was spotless, black obsidian, blank except for his own reflection. There was nothing but himself. He must've been asleep, although he wasn't sure what event was bringing this dive into his own mind on.

It was here he'd confronted his darkness.

It was here he'd learned the sky arcanum.

"Uh, hey brain?" He called out, his voice echoing. "This is kinda a bad time for like, deep introspection or whatever. We're on too tight of a schedule for me to like, deal with the horrors of my mind today." He grinned and gave a jaunty wave to absolutely nothing. "So, is it cool? Can I go now? Great! Thanks!" He put his hands on his hips, ready to stride away. "I'm just gonna go and have some dumb dream about jelly t-"

Callum screamed.

He fell backwards at the sight of his newest, biggest fear standing behind him, a being made of night sky whose body shone with stars. He seemed unaffected by Callum shrieking with terror in his face, only giving Callum a pleasant nod, expression unreadable. "Good evening."

-BREAK-

It was only by sheer force of willpower that Callum woke up, although it unfortunately came with screaming.

"Callum!" They were past the need to share a room, but Ezran still liked to rest near him wherever they stayed. Some things about being brothers didn't have to change. He gently shook Callum awake, eyes wide with concern. "Breathe. Just breathe."

Ezran couldn't have known those words would have such an effect. They echoed with Sarai's voice in Callum's mind and he groaned, rubbing his forehead. Calm washed over him and he gave Ezran a tired grin. "You'd think a sky mage wouldn't need to be told twice, huh? Thanks."

"Are you alright?"

Callum hesitated. "I think so. It was a bad dream. We've had lots of fuel for those, you know?" They could sit around and talk about what plagued them all day, although Callum wasn't sure that he wanted to alarm anyone about Aaravos. The possession was bad enough. He also feared that they might try and just leave him at home, if this continued.

"Hmmhmm." Ezran spread his arms wide, as if telling a fishing story. "Rex Igneous is waaaaay too much taffy for me to eat."

Ezran had a knack for saying what Callum least expected, yet often what he needed. Now that they were older, he suspected it was what Ezran needed too, a barrier of his carefree self against the crown on his head. Callum purged Aaravos's silhouette from his mind with the mental image of an angry dragon made of taffy, laughing and forcing himself to believe it was only a harmless dream. "What flavor of taffy?"

Callum knew the others noticed the dark circles under his eyes. They were polite enough to not comment. No one wanted to talk about his possession anyway, how it stirred up their own personal pain. Callum, although he felt he should probably talk to someone about Aaravos, kept it to himself.

Their journey to find Domina Profundis was everyone's focus. It unified them, it gave them a goal, some form of actionable hope.

Callum hoped to immerse himself in maps and his companion's bad jokes rather than in his dreams.

-BREAK-

The next night confirmed Callum's fear.

It was right where they'd left off.

"Go away!" Callum flung his arms wide, not caring how desperate or childish he sounded, his cry echoing in the void. He'd never had much control as to what happened in this space, but he had to try. "This is my head, so Out!" He knew he must've been tossing and turning in the waking world.

Aaravos was unmoved, standing in the depths of Callum's mind with folded hands. "I wish to speak with you."

"Why?!" He had to admit, it felt good to be able to yell at someone about this, even if it was at the perpetrator. Maybe it felt so good because it was directly at the perpetrator. Callum had been trying to unsuccessfully deal with his feelings after being possessed. Everyone had wanted to ignore it, to put their faith in him, to act like it could never happen again, and now look, Aaravos was already back in his head! "You used me to hurt everyone I care about! You outright said you expected me to 'play right into your hands', I'm not going to listen to a word you say. I'd be stupid to pay any attention to you."

Callum turned, arms crossed over his chest.

Aaravos appeared in front of him again. Figures.

"Yes, anyone would be upset at my method of communication," he admitted. His voice was low, soft, richer than any human Callum had ever heard. He could imagine the centuries of whispers that voice had shaped to its will. "Crude, by my standards. I had to improvise."

"Yeah? You just showed everyone how you can use me like a puppet, and now you come in here acting like I'll be okay with having a little chat? " It was all Callum could do to not stamp his foot.

"I apologize. I see the experience frightened you terribly. It won't happen again."

Something about Aaravos's tone made Callum raise his head, looking at the ethereal being before him as though he was seeing him for the first time. Callum's impression of Aaravos was frigid and distant, but it wasn't what he saw when he locked eyes with him. Callum didn't expect the kindness in his expression. For a split second, the softness on his face reminded Callum of Harrow when he'd been coming around to apologize for something, with such care taken to know that Callum's feelings mattered, even if he wasn't all that great at expressing them.

Callum didn't fall for it.

In fact, the guise of kindness made him angrier. This was Aaravos. Aaravos wasn't capable of such a thing.

"You literally told me, told everyone, that you expect to manipulate me." Callum glared. "I'll never trust you. I don't care how sorry you try to be. Go away."

"You need to hate me right now. That's alright."

"You have no idea what I need."

"Oh, I do." Aaravos's deep voice echoed around him, soft yet powerful. He paced, captivating Callum's attention despite his best effort to be interested in the nondescript floor. "You've lost people dear to you. You've been hurt. You're trying to get friendly with Xadia and forgive and forgive , but your heart still needs a face, a name, a subject to hate, a vessel for your blame. It will never go away, not unless you give in." He bowed. "So I am here. Scream, throw things, do whatever you must- once the air is cleared, we can get on with business."

Somehow, being told to be angry made him calm back down. His feelings weren't for someone else to dictate. Then, he was angry again, because what if getting him to relax was Aaravos's intention? What did he want? Callum clenched his fists, feeling as though every option presented was playing right into Aaravos's hands , yet he had no idea what Aaravos actually wanted and how to deny him it. He tried to think of how a real prince would handle a difficult dignitary. "What business?" he asked, going for his best impression of an aloof person.

Aaravos conjured an array of floating runes with his hand and despite Callum's best attempt at shoving down his curiosity, he recognized some of them from the border of the mirror. They weren't in any books he'd ever seen. Even with the mirror and his Tome of Translation, he didn't have a complete alphabet or any working knowledge of the language. Aaravos nodded to them. "Your education."

Callum suddenly understood how Aaravos had wormed his way into the mind of everyone he spoke to. It was exactly what Callum wanted. He hated himself for being predictable. He hated himself for wanting to start writing down every sigil he saw.

It took every bit of personal strength he had to step back, shaking his head. "No. Not from you."

"I suppose you're going to tell me that you have no interest in other arcana as well?"

"Not interested. Go away. If this is some kind of personal trial about temptation, I'm really really determined to win."

Aaravos smiled with understanding. Callum wanted to punch him for giving the appearance of being nice, but he refused to give into that either. "You're afraid of making a deal with the devil. I am not offering a deal. I am not asking for anything in return except for you to learn."

"Is that what you told the original humans you corrupted with dark magic?" Callum found his courage. "I'm not Claudia. I don't want this, or you."

"That's right, you aren't Claudia," Aaravos commented. "You have something she could never understand. It isn't just your sky arcanum- it's your determination to do things the hard way. Claudia will never learn an arcanum. She is like most human mages, who had a dire need and took the quickest route available to meet said need. You, however, desire a full understanding. You want to do things right. All I want is to help you along the way."

Callum couldn't find a single thing to disagree with, and he hated it. Claudia viewed dark magic as human's magic. She lived it, breathed it. It was as much a part of her as her own blood.

"You're trying to make me feel special so you can use me."

"You are special. It's fact."

"Great, I'm special. I don't need anything else from you."

"You don't understand why I'm here at all, do you?"

Aaravos waved his hand again and the world went from black to being full of sun, blue, and clouds.

Callum stared at the sky around them, suspended in the air by a strong breeze, no ground or water in sight. It was beautiful. It was a part of himself he knew with his eyes closed. If someone asked who he was, it would be this feeling. If Amaya could sign something to represent Callum as a nickname, it would be this- this free floating freedom, the open sky with winds that danced around him and embraced him. Callum could've lost himself in the exhilarating peace of wispy clouds and high altitude sunshine.

But, bad company really ruined everything.

"Yep. This is my sky arcanum. It looks better without the worst guy who ever lived standing in the middle of it."

Aaravos's chuckle was warm. Callum almost wouldn't have been able to recognize it was Aaravos since it lacked the scathing mockery he'd used when possessing Callum. "It is, as you say, your sky arcanum. It isn't the full sky arcanum."

Callum scowled. Did Aaravos want a storm? Fine. He'd bring it.

The serene clouds around them darkened. Breezes turned to howling winds as thunder rumbled all around them. He remembered the storm the primal stone had conjured when he'd shattered it and he focused on that night and then some, deafening them both with a hurricane's worth of wind and rain.

He still wasn't done.

Callum felt like one with the rain and hail. He called down lighting, as bright and powerful as he possibly could, and struck Aaravos with it, shouting as rain soaked him to the bone, as his rage at this man was finally unleashed in an explosive BOOM of raw magic.

It would've killed most living creatures who weren't a storm dragon.

Aaravos raised his hand. He let the lightning hit his palm and then travel down his arm, to his stomach, and then up and out his other hand harmlessly, as if he was a lightning rod. His expression reminded Callum of a purring cat, as if all of the wrath of the sky's storm was nothing more than a pleasant buzz to him.

"Better, but incomplete." Despite the deafening cyclone of hail and lightning around them, Callum could hear Aaravos's soft tone clearly. "Let me show you mine."

For a moment, Callum couldn't process what he was seeing, hearing, experiencing, living. He suspected no human could possibly hold all of this inside of themselves on their own.

He'd never felt so alive.

Every piece of what he was looking at took time to identify, one by one.

They were in the stars. No, they were the stars. Aaravos's form was outlined by the sorts of lines drawn on star charts, but much finer, more detailed. As an artist, Callum couldn't help taking in every line and point, eyes wide with admiration for this new art form. Everything from the curve of his horns down to his boots shimmered against the night sky behind them. Callum raised his own hand and stared, watching as starlight flowed through his veins like molten silver, the outline of his form glowing white.

They were high above the planet below, a planet Callum called home but had never known so clearly before. Though they must've been far away, Callum could feel the winds and clouds as intimately as if he was on the Stormspire. Yet, he also felt the depths of the oceans, the rush of waves crashing on every coast. The moon and sun pulled on the waters of the entire planet and he nearly passed out as he tried to fathom it from his place in the stars- but then Callum was the ocean, feeling the arcanum of truth and light in his left hand, the arcanum of half truth and shadow in the other, the gravitational pull of both threatening to rip him apart, the waves of water and his mind spinning in a circle that never stopped-

"Breathe."

Callum hadn't realized he was crying out, gasping for breath.

That word was sacred to Callum. It didn't belong to Aaravos, yet his soft command worked and Callum was breathing again.

As he calmed down, he felt the earth itself thrumming with life. Plants grew ever so slowly, nurtured and winding their way towards the sky. Slow, but vibrant, teeming with life. Even rocks, both glowing gems and common cobblestone roads felt alive, solid and steady in their hum.

This was Aaravos's sky- his sky, stars, moon, sun, earth, and ocean.

Callum could intellectually grasp it, even as he covered his ears and squeezed his eyes shut, trembling from the bombardment. There was no arcanum disconnected from another- they were all intertwined, as their one and only master knew. They were all a side of the same die.

Aaravos gently laid his hands on Callum's temples and Callum relaxed, able to listen and see without fear of collapsing or exploding. The stabilizing gesture radiated patience. Callum couldn't bring himself to shove Aaravos away, to muster up a sense of danger when all he felt in that moment was safe, supported, and at ease.

It didn't make sense.

Callum was certain that he hated Aaravos, even then, but his sense of it was slipping.

"Why would you show me this?" Callum whispered, now gazing at Aaravos with a mix of fear, wonder, and confusion, magic swirling around them in its purest form, in every form. "Why would you tell me your secrets when I can use them against you?"

Aaravos smiled, pained. The wistfulness tore at Callum's heart even as he reminded himself that Aaravos was supposed to be a monster.

"Why do you assume we're enemies?"