Venator tolerates this only for a few minutes, and Emerald's reward for this behavior is another slap.
Rubbing his cheek with a wince Emerald sees no other choice. Maybe, just maybe, they'll not go that city if they knew the truth.
Venator was about to strike him again, when Emerald finally talks.
He says that his parents will do anything to get him back, and that they are clearly doing something demonic, and that he had to escape through that cave and that's how he ran across the demon things in there.