Thor left Loki alone in a room, with little to do except something he wasn't supposed to. Loki meandered a few paces before something in the tower seemed to call him. There was someone powerful in the tower. 

Loki tilted his head. What was that? Greek, perhaps? His curiosity got the better of him, and he simply left Thor's bedchambers. He focused on the hum of magic that called to him, and teleported.

He scanned his new surroundings quickly, his hands clasped behind his back. It must be a midgardian infirmary, he thought, as he took in the rudimentary technology. He took a step before halting in place.

The two forms were radiating power. The closest to him was a boy, or likely a young man. The other was a lady, and they shared the same features. The purpose, power, and royalty just existing with their presence.

Loki, against logic, let his curiosity loose. These were Greeks, he knew for certain, and he shouldn't meddle, but it was as if it was something he must do. A thought crossed Loki's mind: Could this be what the Norns had sent him for?

The prince began to examine the two. He opened his magic to do so, and quickly realized that things were not simple, not in the slightest. This was probably the most complex, powerful magic that he'd ever seen.

He'd seen soul magic done when he was 76 cycles. That had been done with error, the individual in question lived a drastically shortened life in consequence. This- it was, well, he would have difficulty explaining it to any other.

The souls of the two in front of him were mirrored. Twins, he thought for a second, they must be really close. Then Loki realized that this was much more than twins, because the soul they carried was the same.

"Miraculous." Loki murmured, carefully seeing all the edges and torn places of the halved soul.

He'd lost track of time as he was examining the magic.

Doors burst open, and the first thing one angry billionaire saw was a threat standing over his nephew and niece. "You get away from them!" He bellowed to the magician.

"Absolutely miraculous." Loki said again, mesmerized by the magic. Of course, he was not so oblivious as to leave himself unprotected, and he placed a barrier between himself and whoever would threaten him.

"Stark, calm down! He has done no harm!" Thor tried to shove himself between his angry friends and his brother.

"Are you kidding me? Do you not see him?" Tony raged.

"What do you mean, 'miraculous'?" Natasha questioned as she aimed her upgraded pistol at the god.

Loki properly looked at the mortals, having been able to drag his focus away from the two forms. He spoke to the woman among the group. "They are." He gestured lazily with one hand to the two greeks. "Who came first?"

"What do you mean?" Steve scowled.

"Oh, so we're just gonna have a casual conversation, huh?" Tony angrily grumped, and was ignored by the others.

"I suppose that was the wrong question..." Loki said casually. "Let us start with... How long have they been like this?"

"A few hours." Thor replied, and earned himself a shove from Tony.

"Ah. Then who do you know?" Loki inquired.

"The boy, Perseus Jackson." Thor answered, earning him glares from the mortals.

Loki's eyes widened momentarily. "The hero... Why did this happen?"

"What do you mean, 'why?' We just found her next to Perce after he fought some big bad." Clint glared, aiming his own pistol at Loki's head.

"So this was not planned?" Loki frowned.

"What are you talking about?" Natasha questioned.

Immediately after, a girl slammed open the door. Her hair was wet, having recently gotten out of the shower. "What the hell is going on?" The blonde demanded.

Loki took in her appearance, "The Lady Annabeth, I presume?"

"Yes." She narrowed her eyes. "Who are you?"

"This is my brother, Loki." Thor answered.

"I can introduce myself without your assistance." Loki stated.

"Let's go back to what we were talking about, yeah?" Natasha input.

"Of course." Loki agreed. "It would seem that Perseus' soul has been split in two."

"Excuse me?"

"Care to say that again?"

"What the fuck?"

"Language."

"I thought we were over that, Cap."

"Shut up!" Annabeth yelled. She glared at Loki. "Start explaining why you think my fiance's soul is 'split in two'."

One of Loki's brows raised in question, and his sight drifted to her hand. He looked back to her eyes. "Congratulations." He said sincerely. "Each soul has its own signature. It can't be forged, nor replicated, or changed- tainted, yes- but not changed."

"And they have the same signature?" Annabeth asked.

"Yes." Loki nodded slightly, glad that at least someone was intelligent.

"Prove it." Annabeth stated.

Loki gestured for Annabeth to come closer. The mortals didn't like it, but she pushed through determinedly. "Now what?" She asked as she stood in front of the god.

"Now, you cannot use the same magic as I. Grant me access, just for a moment, to the surface of your mind so that you may see through my eyes." Loki proposed.

"Swear it on the Styx that is all you'll do inside my mind." Annabeth commanded.

Loki looked to her for a second, before meeting her hard gaze with one of his own. "I swear it."

It felt as if a wave of water had hit the earth just below their feet. No harm was done, but the message was delivered. The oath had been made, and if Zeus wasn't king, why would thunder rumble?

"Alright." Annabeth said. "What do I have to do?"

"Just think of seeing through my eyes." Loki informed her, and placed his index fingers gently against her temples. Loki looked to Annabeth's soul, so that she may see her own, then to the mortals and Thor, and finally to the two unconscious greeks. Loki withdrew his magic, and clasped his hands behind him.

Annabeth rubbed her eyes for a moment. "Wow. Okay. So what now?"

"Now?" Loki repeated.

"Yes, now. How do we fix it?" Annabeth demanded.

"Fix it? Lady Annabeth, this has never been done before. In legends, and stories perhaps, yes, but never actually confirmed."

"Wait, is this like a Horcrux thing?" Tony asked.

"Oh!" Annabeth got the reference, and turned back to Loki. "How do we put his soul back together?"

Loki looked at her, and blinked. Then he snorted. "You can't 'put his soul back together'. No, no, let me finish." He said when they began to interrupt. "It's not just Perseus' soul anymore. It's hers, too. The two pieces have been separated in such a way that you can't combine them again."

"So, what? Percy just lives with half a soul?" Annabeth shouts.

"Perseus doesn't have half a soul. He has a whole soul, it's just in two places. Two bodies." Loki elucidates.

"What? And he'll just be fine like that?" Tony demands.

"Well, yes, theoretically." Loki confirmed. "We'll know once he wakes."

"And when will that be, huh?" Tony scowls.

Loki examined Perseus again. He saw the evidence of channeling a great quantity of power, and that things seemed... "Off center." He said aloud.

"Off center?" Annabeth echoed.

"Yes. Whatever he did with all that power, it uncentered him."

"Okay, can we fix that?" Annabeth hoped.

"Yes. I assume that you center him?" Loki inquired.

"Yeah. I do." Annabeth stated.

"Alright. Then I will escort you into his mind, with your permission." Loki offered.

Annabeth nodded. "How do we do that? Is it like the seeing thing?"

"Yes and no." Loki replied casually, before sending them inside without warning.

Annabeth's body fainted without her conscious, and Loki kept part of his conscious within his body and caught her. He laid her on the bed beside Perseus, all while the mortals were protesting.

"She is fine." Loki informed them.

"I thought you said you were going to escort her. Not throw her in." Natasha glared.

"Currently, I am. Now, if you would let me, I'd like to focus on not getting us killed in his head." Loki commented, as cavalier as ever.

"That can happen?" Steve voiced the collective alarm.

"Possibly." Loki replied, before ignoring them.

"What? What's he doing?" Clint demanded.

"Loki has been practicing splitting his conscious. I hadn't realized how much progress he'd made." Thor said, amazed.

~~~~~~

Annabeth found herself in a white room, that was like a giant library. Or storage unit. More like both wrapped up into one. Oddly enough, some things seemed to be floating, or glitching, like in a video game. Some things kept swapping places.

"Percy?" She yelled out. Her voice echoed back to her, in ways she'd spoken it before. Calling for help, teasing him, any way. 

"Loki?" She whispered.

A voice pitched in from behind her. "Oh dear." Loki was casually watching the chaos, his hands clasped behind his back. "You should find him soon. Otherwise there might be permanent damage."

Annabeth gave him wide eyes for a moment before taking off, running through the shelves, calling out for Percy. Objects and memories shifted out of place, and sometimes they had to dodge and avoid particular items.

One area they walked through was particularly dangerous. An arrow flew past and nearly impaled Loki, while a burst of flame came close to Annabeth. Her ring lit up as she used it to defend herself, and Loki's hands remained behind his back as he cast a shield around himself. "An Isle of Self-Loathing. Wonderful." He commented under his breath.

Continuing to follow Annabeth, he lazily noted isles that stood out. "Oh, Doubt." Another isle was proclaimed, "Hope."  Annabeth nearly took off into one isle before Loki snatched her arm and pulled her back.

She glared at him with a ferocity that could kill. "What?"

"Not that way." Loki replied. She tugged, attempting to continue on. "Wisdom's daughter, yes? Then surely you've noticed that these isles have an affect on you."

She paused. "Yes. I thought I was imagining it."

Loki rolled his eyes. "Imagining in a mindspace is a very dangerous thing, Lady Annabeth."

"Mindspace? Okay, I can figure what that means. Why not that way, though?" She asked.

Loki huffed. "Look into that Isle. What do you see?"

"This whole thing's a maze, I see paths and corners and dead ends." Annabeth retorted.

"Yes, you are correct. But Lady, you are looking for Perseus, not the end." Loki released her arm when he thought she wouldn't go dashing into the isle. 

"What do you mean, the end?" Annabeth frowned.

"That Isle is probably the most dangerous one of all, and by my estimate from what I've seen so far, the largest." Loki looked in warily. 

"Why? You were naming them before, weren't you? I don't speak Asgardian." Annabeth realized.

"Yes. I do believe this one to be 'Failure'." Loki replied. "Now, we need to find the Isle he'd be in."

"That one." Annabeth said with startling conviction.

Loki sighed. "Fine then. Prepare yourself, it won't be pleasant."

And it wasn't. The ground was like quicksand, the shelves were like thorny vines, the air was cold and thin, and other unpleasant things. Loki really hoped this was worth the trouble as he batted away a severed, floating hydra head. He also hoped it would end soon as he nearly slipped on blood pooling over the ground.

Then Annabeth found Percy. He was hollering about, trying to find something, someone. Annabeth dove in and wrapped her arms around him, speaking in commanding, soothing tones. At least, that's how Loki thought Perseus would perceive it.

Loki hung back as much as he could, feeling a bit awkward at being a bystander. He busied himself with not getting ambushed. He noticed the mindscape shudder, and things drifted back to their places. He glanced over at the couple and saw that they seemed to have figured it out. Then he teleported beside them, and tapped both of their heads.

~~~~~~

With just as much warning as when she entered Percy's mindscape, Annabeth was thrown out of it. Both pairs of eyes snapped open, and disorientedly adjusted. "Ugh, what just happened?" Percy groaned.

"Percy!" Tony exclaimed, and made his way closer to Percy. The others closed the distance too, asking him how he was in different ways. Loki slipped away from the group.

Suddenly Percy remembered. "Tartarus! What happened-?"

"You beat him. We won." Annabeth assured him.

Loki tilted his head slightly. Tartarus? Yes, that was what he'd said. Then the great power he'd channeled had to have been as strong as the entirety of the Greek pantheon. In order to achieve that though, well, only the king had that ability. 

"How did you defeat him, Percy?" Thor asked him.

"I just... Well, a lot of gods helped me." Percy said, not wanting to share the extent of what he had done. Then he felt like an idiot. The Fates. What had happened with the Fates? What had they done? Frantically, he looked down at himself, and tried to tell if he was still a god. 

"What? What's wrong?" Annabeth demanded.

"The Fates! They talked to me! They gave me a choice, but I ran out of time before I could decide and-" Percy rushed through his words.

"What?" Tony and Steve yelped as Clint and Natasha stared.

"Of course." Loki realized.

Percy heard him and his eyes snapped to the other god. "You!"

Loki looked mildly offended. "Me?"

"You were in my vision! And your eyes are green! See, I told you!" Percy informed his friends. "You were with my sister- my sister!" Then Percy's eyes landed on the girl in question. "That's her." He breathed.

Loki took a single step closer. "What did the Fates offer you?"

Percy dragged his gaze from his sister to Loki. "They said that... It was really confusing... But I could be mortal, or my sister wouldn't exist? I think?"

Loki nodded. "So you ran out of time and they picked for you. It looks like they chose a different option, though."

"What do you mean?" Percy frowned.

"Perseus, they split your soul. You are still a god. And she is a goddess." Loki shared simply.

"I'm still a god?" Percy blinked, disappointment filling his voice.

"It's okay." Annabeth whispered, and snuggled into him. 

Percy instinctively wrapped his arms around her. He looked back at his sister. "Why isn't she awake?"

Loki walked closer to find out the state of her mind. He internally winced when he got a little too close to her mind. "Her mind is in chaos."

"Like Percy's was?" Annabeth asked.

"Yes and no, mostly no." Loki replied.

"Can we fix it? Like I did with Percy?" She pushed.

"No." Loki answered. "Perseus's was off center. Her's is chaos. I would have a hard time getting close. There would be no chance of success if you were to tag along."

"You can help her." Percy said.

"Excuse me?" Tony and Clint both blurted in unison.

"I had a vision, and you helped her. I know you can." Percy said with conviction.

Loki gazed back to the girl. Somehow, deep inside him, he knew he would help her. The prince pulled a chair over so that he could sit beside the girl's bed. 

"How can we trust you?" Clint asked the god. "Your whole thing is lies."

"I have had my mind taken from me, and returned. I think that it is my duty to offer this girl the same courtesy." Loki told him.

"Sure." Clint scoffed.

"Why is it so hard to believe that I wish to aid another?" Loki asked no one in particular.

"You wrecked New York." Tony glared. "You controlled Clint, you tried to control me-"

"I did?" Loki inquired.

"Don't play innocent-" Clint began, but Loki ignored him.

Loki turned to Thor, and spoke to him as if he was the only one in the room. "They do realize I don't remember, right?"

That, for sure, caught their attention. Thor shook his head.

"What do you mean, you don't remember?" Steve questioned.

"Everything from that time is blurry. My memories didn't survive breaking the control. It was complicated, and I'd rather not talk about it." Loki stated, and sat down. "Now, I have a feeling this is going to take a while. I suggest you to go about your business and leave me to my work."

A/N

I'm having fun with Loki. Are you liking him so far?

Btw, ~~~~~~ Is a time skip or a location change.

Please keep in mind that updates will not be as fast as they were over the summer, because I have school and homework.

Make sure to comment and vote if you enjoyed!

Side note: If I made a one-shots thing based off BBC's Merlin, would you read? (They'd be long, single chapters most likely)