Zeke
Zeke just stared at the dark mage in disbelief. At least, it had to be disbelief, how else would you explain his reflection on his vessel's widened eyes? At least... until he pulled out that thing.
What?
"Wah! Where did you get something like that! Lemme seee...!" He circled around the gem with an interested look. The mask of shock and surprise broke as a small smile took its place, along with another mask that was even harder to pinpoint. So he laughed genuinely. Its as if that man had told him a funny joke, or more like he realized he had gotten pranked and couldn't help but find it kind of funny. "Fuhahahah! I see, I see! I think I get it now. Thanks..."
He moved to snatch it immediately.
Or... tried. His eyes widened, he struggled with a gritted rictus. However, he couldn't so much as move. His hand reached out for it, but couldn't inch forward a single step, like if he was encased in diamond. His body trembled trying to get it, but ultimately stopped entirely, and he turned his glance to Eru with a sly grin, even though his body was sweating all over from the futile strain. "You're a real ass." He didn't say it maliciously, more in a friendly oh dang it, you're really going to stop me? I called first dibs man. Fine, fine, if you're so desperate, I'll letcha have it.
Yeah, that sort of thing.