The obligatory exposition chapter. I'm picking a very different route from your usual soulmate!AU plot so bear with me.

For several long seconds, the only sound around them was the distant rumbling of the wall-mounted cannons. Mikasa rolled her sleeve down. The first shock was wearing off quickly. Still, out of all the scenarios, all the possible people with whom she could have been matched, the man who was considered the humanity's strongest soldier had never once figured in them.

She didn't feel anything different towards him. There was a respect for his skills and a gratitude for his aid earlier but no sudden desire to be close to him. She had told herself before that the stories were exaggerated but only now did she start to believe it.

And with that realization, it became easier to accept this.

"What happens now?" she asked and he looked up.

"Weren't you told?"

"No, the doctor just said to leave it to chance."

"Fucking useless," he muttered. Mikasa felt a spark of annoyance but his comment didn't seem aimed towards her. "There's supposed to be a protocol in place."

"Supposed to be?" she asked. "You don't know either?"

Levi shrugged, looking to the side.

"I only know the basics. Matched pairs are more effective in a combat so the army try to find all of them. Sometimes they even change the branch assignments to get them together."

Mikasa remembered the doctor writing something down in her file just before she was dismissed.

"Why wasn't I told that?"

"I wouldn't know." He paused. "But I know someone who can explain better. Follow me."

She did, not because he told her to but because she wanted to know more. Not only did it seem that everything she had heard about the Marks was wrong, it was like the information had been kept from her on purpose. She didn't know who or why would have done that but she wasn't happy about that. Not happy at all.

The encampment the Survey Corps had set up was full of activity. Most of the soldiers were gathered around two Titans, tethering them to the ground with thick chains. The person in charge was the squad leader Mikasa had met briefly earlier, although she didn't get their name.

"Careful! Don't hurt them!" they shouted and Mikasa thought they might be a woman but it was hard to be sure.

"As long as their napes stay intact, they'll survive," Levi said. "Your squad can finish this, I need to talk to you."

"Huh?"

Levi was already heading for the command tent and after throwing a curious glance at Mikasa, the squad leader followed them both inside.

"What's going on?"

"Show her," he said as he rolled up his left sleeve and Mikasa followed his example. The bright red sword-shaped Mark stood out against their skin. The squad leader peered at them and then laughed.

"I knew it! I knew it wasn't a mistake!"

Levi scowled.

"Yes, you were right. That's not important right now."

"Not important? Levi, everything up to this point has shown the matched pairs to be physical and mental equals or close enough for the differential not to matter. An average increase in the combat effectiveness is twenty-three percent. Twenty-three percent increase on your results would be incredible!"

Mikasa got the distinct feeling of missing something. The way the other two talked, it seemed as if they had had this conversation before. She hated being left out of the loop.

"Hange, she didn't know!" Levi finally managed to interrupt the tangent that Hange was on. That deflated the woman quickly.

"What? But she's a graduating trainee. She should have been told."

"I wasn't told anything other than how rare the Mark is and that I should leave finding my match to chance," Mikasa recounted for the second time. The change that came over Hange was scary. She pushed her goggles up, took a deep breath, let it out. She did so again. And again. After a minute, she pulled her goggles down and turned to Mikasa.

"When did your Mark appear?"

"Two years ago."

"And you told the doctor immediately?"

"Yes. I mean, I heard the stories but-"

"Most of those stories are exaggerated nonsense," Hange cut her off impatiently. "Unmarked people confusing cause and effect or mistaking things they don't understand. That's not the point. Levi's Mark has been recorded for six years. You should have been told within a month of your own appearing."

"Why are these Marks so important?" Mikasa asked. "If the stories I heard are wrong, then what's their point?"

"The stories are not entirely wrong," Hange explained as she sat down at the table, waving for Mikasa and Levi to do the same. "The Marks are rare and people bearing identical Marks are each other's perfect match in a physical, mental and emotional sense. However, having the same Mark doesn't make you fall in love instantly, nor does it mean that you have to end up together romantically. The Mark doesn't take away the free will."

Hange paused and rolled up her own left sleeve. The red mark she bore was shaped like two connected spirals.

"Case in point, my relationship with my match is strictly platonic. We are very good friends but we decided not to pursue anything more. Given who we are and what we do, it would bring more trouble to become involved than not. The importance of the Mark, especially activated Mark, lies in something else. It creates a bond of sort, an awareness of the other person. It's not exactly reading minds but it comes very close. As the connection finalises, which usually takes about a week since the activation, you'll be able to feel each other's presence and emotions. You'll become attuned to each other on a subconscious level. It works up to five kilometers although the accuracy drops drastically once you pass the three kilometers mark."

Mikasa sat there in silence, absorbing the information. In a way, it was almost worse than the stories she had heard. To have that kind of connection forced on you through no fault of your own... Then again, she could see why the military would want to utilize this. Pairs of soldiers able to communicate without words, that kind of thing was extremely useful.

"You should have been told all of this as soon as your Mark appeared," Levi said into the lengthening silence. "There are regular checks to find the matches to Marked soldiers. If you weren't told, it must have been on orders from above."

"Well, it's the MP who staff the trainee camps. They might not have wanted to let you two meet," Hange mused. "The accumulation of power in Survey Corps must have worried them."

"Politics!" Levi spat out and Mikasa had to agree with his tone.

"What's done is done," Hange said. "You won't be able to join the MP now as Levi's assignment to Survey Corps takes precedence over your placing in training. You're this year's number one trainee if I remember right."

"I was going to join the Survey Corps anyway," Mikasa said.

"That's great then," Hange said with a smile. "You'll be assigned to Levi's squad at first but the plan has always been to have Levi and his match form a two-person team eventually. I devised several exercises to help you develop your teamwork. I just can't wait to see how you do."

Mikasa could have sworn Hange's eyes glowed for a moment. It was most likely a reflection of light on her goggles from outside but it was fairly unsettling.

"I should go. I still have to report to Rico."

"Right. I'll see you later. If you have any questions about the Marks, don't hesitate to ask."

Levi followed her out of the tent. As she checked her equipment - a force of deeply ingrained habit - he cleared his throat.

"I'm sorry about this, Mikasa. People usually get the chance to decide if they want to go through this."

"You didn't know," she replied and she meant it. This wasn't his fault either. If anyone was to blame, it was the unknown people who had decided to leave her in the dark.

"Be careful," he told her. Before she could protest, he continued. "Not with the Titans. You weren't told about your Mark for a reason and there might be people angry about getting their plans ruined. Keep quiet until we can shield you in the Corps."

She nodded, wondering if the concern she felt was coming from him or was just a projection of her mind.

"Yes, sir. I will."

He nodded at her and she shot her anchor out, swinging up above the houses, feeling his gaze on her until she disappeared out of sight.

A/N: Why let the Marks be nothing more than glorified birthmarks when you can do so much more with the concept? Also, that slow burn tag is there for a reason.

Lastly, Hange's Mark signifies wisdom, leadership, spiritual enlightenment. There are several variants and meanings for the spiral but the basic gist is that.