Chrollo spends a moment trying to picture what daemons the troupe might possess if they were from a world where such things happens, but it's difficult. They all changed so much when they decided to form the troupe as it is now, and have changed more since then.

"I see, and if my spider were a daemon rather than an omen what would that tell you about me?"

The rules for omens are possibly similar, but also different. If he'd gained an omen when he was a child Chrollo knows its form would be very different from the twelve-legged spider he has as an adult.