[Oh. That might not have been the best choice of words.]

Uh...it's not really their "heart", but more like their "heartbeat". No, that's wrong. Zombies have those too, even if it's hard to figure out...

[Looking for the write way to word it, Duster moves his hands around with each new idea. It's their spirit? He mouths a "no" and forms a fits. Their essence? What is an essence? He looks in a different direction.]

Everything has a presence, right? You can feel it in the air, especially when you're fighting them. It's like...when you fight zombies, it's kind of off-kilter, since they have trouble walking. And when you're fighting machines, since they're all metal, you have a hard time figuring out how they feel and what their next move will be. Huge, heavy things have a slow tempo, and...

...am I making sense?