The fact that his sister was quite frightened made Gotham even more brave. With his chest puffed out a little, he peered into his sister's green eyes and replied, "'Course not." Cambria still seemed hesitant, though, and the boy would not rush her. He settled down to his haunches and curled his tail around his side. The darkness made every direction seem like every other direction, and if there had been more possible paths to chose Gotham would be quickly lost. He kept track of which way they had come from, and which way they were going, and that was all.
He wanted to be patient, but after a few moments he was itching to keep going through the tunnel. It was dark and kind of scary, but that just tempted the boy even more. He would conquer the darkness, and he would learn what was down there. Likely it would be more of the same - rocks and dirt and stuff, in keeping with the opinion he had previously voiced - but perhaps there would be treasure! He hadn't thought of that before, and now that he did their little adventure seemed even more exciting.
The boy resisted his urges enough to take a moment to make sure his sister wasn't too scared. "Are ya ready ta go?" he asked cheerfully, still peering into her eyes with his own wide blue ones. Her uncertainty was very clear, and again he reminded himself not to force her. It would be harder to explore completely with someone who didn't really want to, because then he would always have to be making sure she was okay. When he was older he could come back to the caves by himself, or with another boy. All boys like exploring, of course! It wasn't his parents fault that they had only given him sisters, but maybe soon they could get him a boy to play with. That would be very nice of them.