Precisely! 

Thank you!   Glad you finally decided to read. 

Finally they got to check out the underground city, known as New Ouroboros. The building structure was much different from the buildings of the surface. They had a more ancient style and went high enough to support the ground above them. There was glowing slime, glowing rocks, some of which Zephyr realized to be aurora minarels and also normal street lights that kept the underground world lit. There was many serpentine, Zephyr had already seen quite a few serpentine on the surface, but most of them were from a distance, down here though she was walking close enough to see their scales and glowing eyes. She had learned about the serpentine and their dark past, but she also knew that nowadays they just wanted live in the world peacefully. There was also many people as well, some chating normally with serpentine or other humans, others buying from the many small shops within a large market area. While others along with serpentine used bikes, skateboards, hover broads and other small transportation on the thin dirt road that stretched throughout the seemingly endless underground city. They walked through the underground city for a long while. Zephyr finally asked 
"How big is this place? "
" Quite possibly bigger than Ninjago City by now, it's been growing for years, using the tunnels the serpentine made when they were released by our very own Sensei Lloyd. " Explained Lisa.
"So the city just keeps going? " Moe asked as he looked around. 
" It sure looks like it." Commented Zephyr. 
" It ends eventually of course, but it would take you awhile to find it. " Said Lisa. 
Suddenly the sound of screaming could be heard from a tunnel and road that vared off the main one. 
" Oh dear, I was afraid we might have to encounter something like this." Said Lisa looking as if she knew what horrible things may lay ahead.
"What do you mean?" Asked Zephyr as the four them ran in the derection of the screaming. 
" The cities may be beautiful, but all that is just a mask over what a horror story they really are on the inside nowadays... " Lisa explained as they kept running.