It's fascinating how long Levi can go without sleep. Those dark circles under his eyes really proved as much, but still. The man can go a day or two without sleep and still slaughter dozens of dozens of titans with ease like it's a routine.
That, and training. He trains just as hard as he works everyone else, just as harsh on himself as he is on others. He'll get by with a cup of tea. A cautious one too. He's so, so attentive, head snapping in the direction of any sudden sounds.
Reflexes on point, hearing, sight, and all. If he were to be allowed some sleep at all, he wouldn't even get down to hours. He'd be the last to sleep out of a group of people and also the first to wake up, no matter how late or early it was. Levi hardly got as much as a nap.
Oh, but when he did? He's out cold. That's another fascinating thing. How steady he sleeps. Like a rock, or maybe a baby. Hange tried waking him once and that didn't turn out nicely. Since then, nobody has tried to wake him up from his rare deep sleeps. He deserves every bit of it, after all.
No matter how gently or carefully someone tries to wake him, the scouts can only imagine the dark aura surrounding him as soon as his eyes blink open. He'll be a total harsh ass to everyone the rest of the day. Harsh orders, that scary tone of his, and even more intense training as if the current routine wasn't intense enough.
He hasn't slept in two days. Usually, that'd be a so-so span of time and he wouldn't be that tired. Something's up and he's been slumped since noon yesterday and late afternoon today. He's missed two meals and a training session. No one has dared to try waking him up.
So, why did you? "He's going to have us run laps around the entire forest, I'm telling you." The younger scouts behind you were practically shaking in the knees as you approached Levi's bedroom door. "Let her," Hange chimes in. "She'll be alright."