Noctis!

                                    

                                          
After exploring the island, Robin and Brook came across a hole near a big cherry blossom tree. 
"What do you think this hole will take us to?"
Robin placed her hand on her chin and thought with a serious expression
"Maybe to hell!"
"Yohoho, but I don't feel the cold energy from the underworld."
"Will only know when we jump down."
"Yohoho... Robin-san you are becoming like Luffy-san."
Robin ignored Brook and sprouted many hands until who knows how deep reached the ground and used them as a ladder to climb down. Brook shed a tear and followed suit. 
"How deep is this hole?"
"We will reach there in 2 hours if we climb at this pace."
"Excuse me, Robin-san let me carry you."
Brook gently held Robin in his arms. The arm disappeared leaving flower petals behind and Brook began running down as he did while he ran on water.
And they reached the ground in 5 minutes. 
"Thank you brook-san!"
"No problem, but if you don't mind can I see your pan-"
"Brook look a moon!"
"-ty, what a moon!"
"There also seem to be stars and a dead tree."
"This place looks similar to Thrillerbark."
"I don't see any graves though and this place looks really beautiful."
"We are underground so it does make sense there to be dark, but how is there a moon and stars, and how is it possible for plants to exist here?"
"We are in Grandline, so an underground city shouldn't be that surprising."
"Right!"
Both walked toward a dead tree. 
"It doesn't talk... this tree seems to be over 200 hundred years old."
"Robin-san I think I see a light from there, although I don't have any eyes since I am a skeleton... yohoho...."
"A human?"
"They seem to be running towards us."
A person with a lantern came running towards the duo. 
"A-are you guys from the above?"
"Slow down kid and if you mean from there up on the ground then yes."
"You guys really from above... how cool."
"Ehm... kid what is your name?"
Robin stared at the kid, a girl... and why was she wearing a mask? 
"I am Luna!"
"I am Brook and this is Robin"
"A talking skeleton."
"Yohoho, Luna-san can you tell us where we are?"
"Sorry, I got too excited, I haven't seen any outsiders in my whole 8-year-old life. We are in at Noctis, the city of eternal night."
"Noctis, a beautiful and suitable name for this place."
"Thank you, Miss Robin!"                                                                                                                                                                                                                                                                                                                                                              This kid is like a sunshine, just like Captain-san. Robin patted the child's silver hair.