Erwin's guess

"So, Bai Yu, what are you saying?"

Bai Yu sat across from Erwin, confidently explaining his theory. Well, it was technically a theory.

"There weren't any Titans there at the time, but then, for some reason, a bolt of lightning struck. I'm not sure it was lightning, but it looked something like that. Then a Titan appeared. Obviously, it wasn't a Titan to begin with. Something turned into a Titan. As for what that something was..."

Bai Yu left the rest unsaid, but Erwin understood.

"Then what exactly is our enemy?"

Erwin stared intently at Bai Yu as he asked.

"Humans, probably."

"Who the hell knows whether there are humans in the outside world?"

Erwin's pupils contracted sharply at those words. Bai Yu noticed, of course. He also knew Erwin's dream. This was a man willing to sacrifice everything to prove that humans existed outside the Walls, whether that meant himself or others.

"Why do you think that?"

"Go ask former Commander Keith. Didn't he find Doctor Jaeger outside during an Expedition Beyond the Walls and bring him back? How could a human possibly survive outside the Walls?"

"How do you know about that?"

"I asked Doctor Jaeger."

Of course, Bai Yu hadn't asked him, but he couldn't exactly say he'd watched the story, could he? Doctor Jaeger was gone anyway, so he might as well pin it on him. It wasn't as if Erwin could raise the dead.

"It's just a theory. I never paid much attention to it before, but now that I think about it, how could a human survive outside the Walls? That's practically an established fact. And he was so far away. The gate in Wall Maria barely ever opened. If someone really had run outside, wouldn't the Survey Corps have spotted him? They're not blind."

Erwin offered no rebuttal. He simply watched Bai Yu in silence, a light flickering in his eyes.

"If he couldn't have gone out from inside the Walls, doesn't that mean he could only have come in from outside? Of course, that's all just speculation. Maybe someone dug a tunnel and escaped. We could give that a try."

Bai Yu shrugged as he finished.

"That concludes my report, Commander Erwin."

Erwin said nothing. He interlaced his fingers and pressed them against his forehead, completely lost in thought.

Seeing this, Bai Yu quietly stood up. I've finished my report. What am I still hanging around for? Time to go back and sleep.

Long after Bai Yu had left, Erwin finally raised his head. Looking at the empty seat across from him, he chuckled softly, though there was no telling what conclusion he had reached.

"Bai Yu, recruiting you into the Survey Corps really was the right decision."

Of course, Bai Yu was already gone and couldn't hear him.

Erwin now had a lead, but he still needed to verify a few things before deciding how to act.

Back at the Training Corps, Bai Yu found everyone still holding their horse stances. He sat down nearby without disturbing them, thinking only about how to deal with the four Titans.

He had spent the past year improving Xiate and her companion's abilities, and had almost forgotten about those four.

How should I deal with those four? Dig a pit and lure them into it? That's right! Dig a pit and lure them in! I'm a genius.

But that would require Erwin's help again, and he had no good explanation to offer. There was no way to explain how he knew they were Titans. Erwin might even start suspecting that he was a Titan too.

Who the hell knew whether that might happen?

After some thought, he decided to wait until they made their move two years later, then deal with them one by one.

I'll develop that Thunder Spear over the next year. Otherwise, I won't be able to blast through the Armored Titan's armor and hardening.

A light flickered in Bai Yu's eyes as he considered this. With his plan settled, he stopped dwelling on it and stretched.

A week later.

Bai Yu looked at the cadets below him.

"Tomorrow, we're heading outside the Walls on an Expedition Beyond the Walls. It'll take two or three days at most, one or two at least. During that time, Instructor Keith will continue teaching you how to use the Omni-Directional Mobility Gear. I'll resume your Hand-to-Hand Combat lessons when I return."

At the news that Bai Yu would be gone for a day or two, some were delighted, while others felt a little disappointed.

Bai Yu then dismissed them, leaving Keith, who stood behind him, to oversee their Omni-Directional Mobility Gear training, running, and other exercises.

Bai Yu had also asked Erwin about the objective of tomorrow's Expedition Beyond the Walls. Their destination was Shiganshina District, and they would clear as many Titans from the route as possible. Erwin had asked Eren's mother about some of Doctor Yeager's habits at home.

He had questioned Eren too. Although Bai Yu didn't know what they had asked, he knew Erwin must have learned something.

That was because Bai Yu had sensed a change in the way Erwin spoke. There was an urgent desire to verify something. It was buried very, very deep, but Bai Yu was sensitive to that sort of thing, and Ming had picked up on it too.

The thirty-sixth Expedition Beyond the Walls began.

Bai Yu's Support Squad raced between the Scout Squads' positions. This expedition happened to coincide with a crescent moon, and Erwin's objective was to push all the way to Shiganshina District!

This time, Erwin had assigned Levi Squad to the Support Squad as well. Bai Yu's squad took the left, and Levi Squad took the right. They advanced at full speed, heading straight for Shiganshina District.

No one knew why Erwin was so determined this time.

Bai Yu knew, and he was pleased. Erwin really was clever.

Their pace picked up sharply, but the problem was that they encountered Titans more frequently than usual. Still, thanks to the Support Squads, their losses weren't too severe, although several people were killed by Titans.

By that afternoon, they had reached the place that had taken them a full day to reach last time. It wouldn't be long before they arrived at Shiganshina District.

If they pressed on at full speed, they could arrive in roughly another half day.

However, the other four members of Levi Squad sat on the ground as though paralyzed. They had killed nearly twenty Titans along the way. It was their first time fighting Titans one after another without a break. If Levi hadn't been there, they would almost certainly have lost someone.

Some members of the other Scout Squads had still died, though.

Bai Yu's squad was in slightly better shape, but they were also sitting on the ground, reluctant to move. They had killed more than twenty Titans as well, over half of them at Bai Yu's hands.

Erwin waited for nightfall. He intended to push straight to the breach in Shiganshina District in one go in the dead of night.