Achilles heeds Stab’s warning and withdraws his hand; he knows that same protective ferocity. But he can’t deny Scout’s accusation. Answering Gavroche’s question might help explain, though.

“The person I love most in this world fell to our enemies, and his loss illuminated everything. I came to see how hollow, how pointless the war had become—nay, had always been.” He picks up the enchanted stone and rolls it between thumb and index finger, as if it had revealed this truth to him.

“It was a revelation that came far too late, and at a terrible cost.” Achilles grips the stone in his palm, knuckles white. “And … if I was truly wise, I would have returned home, but I remained to kill the man who killed my beloved—as if this vengeance would bring him back to me.”