[He notices how Silco behaves with the civilians of Stygia, eyes tracking the man until he's joined by the body. It seems he wasn't remiss to hand off the questioning to Silco; while he could have come to the same results, his own personality is coarse and blunt by comparison, and he'd sooner prefer to learn the answers to his questions more indirectly.]

Yeah. In the Netherworld, the only way to make anything durable is by imbuing it with a soul. Soul-forging. Otherwise it'll disintegrate. I've seen it happen. [He'd found a few knives, but they hadn't lasted. Not long enough to serve any real use more than once or twice. Soul-forging is a topic he's had to dig up information on, because the people of Stygian seem so reluctant to approach it.] ... The souls of those like us, Restless. You were attacked by the Reaper when you first woke in this place. It wanted your soul.

[It's an incident Silco will likely remember, after he was ripped out of the Shroud.]

To obtain a soul, the person must be killed.