No, he'll never understand. It isn't just because he hasn't lived it, those missing four years, that last struggle - it's because to Levi, it's a simple fucking decision. There's no justification for it and never would be, no reason that could ever convince him that such horrific loss of life on that scale is necessary. Sometimes people died because shitty things happen beyond their control, and other times there's definite, definitive sources of blame, decisions that led them there, that people made knowingly.

He doesn't understand the fucked up circumstances, but even if someone could explain it to him, Levi still doesn't believe in this sort of "inevitability" when there had been a choice no to.

The subtle shifts in Eren's expression don't go unnoticed, but when he still gives him nothing and starts to leave, that anger flares to life all over again.

The flash of gray eyes is all the warning he gives before he strikes out with his foot again, kicking Eren's shin out from under him and driving his knee into his chest when he buckles, feeling ribs crack.

"I didn't fucking say you could go," he hisses, looming darkly. "Why the fuck did you do it, Eren? What did you think it would accomplish? Could your puny brain not wrap itself around anything else?" No answer would absolve him, but Levi wants to hear it anyway. Another kick and a heel planted to one shoulder pushes Eren onto his back, holds him down as Levi leans down to glare menacingly. There's nothing but rage and pain in his chest now as he stares into a face older and so changed than he last knew. Bring him back, part of him wants to scream, mourning.

Instead he just waits, tense with fury, fists clenched so hard his hands ache, to see if Eren will just deny him again.