Dragon brought the two of them down below the fortress via a secret passageway that only himself and the other executives were aware of.
"This island, like many others, used to be a place with a thriving civilization. That is until a world noble came to visit and decided to take the kingdom's beloved princess as a slave. The king as well as the people were outraged by his reprehensible actions, so they killed the world noble and rebelled against the World Government. Since the kingdom did not produce anything of great importance for the World Government, it was deemed easier to annihilate it via buster call, than to capitulate them." Dragon said.
"How very short sighted of them." Cherry commented.
"Indeed, but they are not at fault for trying to resist tyranny. Even if the result was expectedly hopeless." Dragon said. His voice was tinged with regret as if he felt in some way responsible for not being there for them, even though the state of the ruins would suggest this happened at least a hundred years ago.
The walls of the secret passageway felt more like a tomb than a castle until they reached a large wide open room. At the center of the room stood, Dragon illuminated the familiar dark cubic shape of a poneglyph with his torch.
"I've always wondered what words those ancient peoples wanted to convey to the future. Professor Clover once told me that most of them contain histories either lost to time, or more likely erased by the World Government. We both knew that I suspected there was more to them, but I neither asked nor did he volunteer that information. I could at least infer that they likely told the truth of the Void Century in some way, and perhaps contained information on the ancient weapons." Dragon paused and looked into Robin's eyes.
He smiled at her. "I can see in your eyes that you would never tell me if they did write of the ancient weapons on them. That is good, I do not want the temptation. I should think I would never choose to seek them out, but I am only human."
Robin could hear the truth to his words and gained some more respect for the man. She glanced to her side at Cherry and wished she could say the same about her lover.
"Why are you looking at me like that? I'm not going to revive the ancient weapons. I promised not to, remember?" Cherry said with the least trustworthy face in the world.
"I suspected it might be the case since earlier, but are you able to read the poneglyphs as well?" Dragon asked.
"Yes, but she only agreed to teach me because I already memorized the blueprints for Pluton. So even if we did find information about the ancient weapons on one of these bad boys-" Cherry slapped the poneglyph. "-then it wouldn't matter in my case."
"I see. For some reason that is deeply concerning to me for reasons I cannot comprehend." Dragon said, a chill going down his spine.
"No, that's the normal reaction to Cherry. It would be more concerning if you didn't feel concerned." Robin replied.
"Enough chit chat, we've got a big rock to read!" Cherry exclaimed, pushing Dragon around the side to light up the writing.
They finished reading the poneglyph after a few minutes at about the same time. Robin was more experienced in reading them, but Cherry had better mental processing speed which roughly evened out the times.
"Hmm…" Cherry hummed thoughtfully.
"Can you share what it says? If it isn't about ancient weapons of course." Dragon asked curiously.
Before Robin could say anything, Cherry spoke up first.
"It's a very naughty love letter written by the mason who carved the stone." Cherry spoke with an amused smile.
Dragon turned to look at Robin seeking a serious answer.
"No, she said it like it was a joke, but that about sums it up. Excluding the 'naughty' part as it's actually quite eloquent. The individuals involved can be inferred to be of significant status from the context, but that's all." Robin explained.
Dragon was a bit dissatisfied with the result. He'd hoped it would be some interesting bit of history, but he supposed that was just his bad luck.
Neither Robin nor Cherry elected to mention that the poneglyph also contained instructions on how to find another poneglyph. Unfortunately, it pointed to an island that Robin was already quite familiar with, Ohara.
Dragon was a shrewd and perceptive man, but he couldn't see through such well practiced liars as them. Not that they were hiding anything of importance from him in any case.
They returned through the secret passageway to Dragon's office.
"Say, can you teach me more about haki's advanced uses?" Cherry asked.
"Hmm…" Dragon hummed in thought. Although Cherry was friendly with his son and with Robin, his instincts told him that teaching her would turn her into a real monster.
"I can agree to that, on the condition that you take up some work for my cause. Preferably without letting anyone know you're doing it on our behalf. Normally I only train those who are loyal to the cause, so I'm already making a concession here." Dragon offered.
"I won't do assassinations." Cherry countered.
"Deal." Dragon said with a cunning smile. He wasn't planning on using his son's friend as a contract killer anyways.
"Tsk." Cherry clicked her tongue, realizing she could have gotten more out of him since he accepted so quickly.
Dragon had some work to do, so Cherry instructed Robin in some martial arts, the basics of Traceless Steps, and answered some questions about cultivation that she had.
After the sun went down, Dragon came to find her to begin their haki training.
"Tell me what your current level is so I know where to begin." Dragon said.
Cherry told him that she had standard proficiency in Observation Haki, fairly good Armament Haki with a natural talent for the internal destruction advanced technique, and finally basic Conqueror's Haki.
"Let's start with observation haki, then. Put these on." Dragon handed her a blindfold.
Cherry naturally knew what they were for. "Kinky."
Dragon didn't reply to her provocation. He would have thought it was a way to deal with being nervous, but after interacting with her, he knew she was just like that.
"Sensing incoming attacks is pretty easy when you're fighting a beast or a particular dull witted human." Dragon said.
*Wack!*
Cherry felt a hand slap her upside the head. Her observation haki didn't pick it up at all. Of course she could use Life Sense to get around that particular problem, but that would defeat the purpose of the training wouldn't it?
"People are cunning and can hide their intentions. The purpose of the blindfold-"
*Bam!*
A punch to her stomach.
"-is to teach you to sense the true intentions of your opponent, behind their deceptions." Dragon said.
"You're gonna teach me how to do that as well, aren't you?" Cherry asked, unfazed by the two attacks.
"You've already been doing it naturally from what I saw during Marineford. I can teach you how to do it consciously too, though." Dragon answered.
*Pow!*
A mean right hook to the jaw.
Cherry had sensed something that time, but it was a trick aa the punch came from the wrong side.
Dragon beat on Cherry for a few hours before calling a quits for the night.
"We'll start again just before dawn, don't be late." Dragon said, walking away.
Dragon was secretly very impressed with Cherry's natural resilience. Hitting her felt like he was attacking one of Vegapunk's robots, only she was clearly made of flesh and bone. PErhaps she fused steel into her body with her devil fruit? She was heavier than expected of a woman of her size, but not to the point that she could be made of metal.
Cherry also had some thoughts about Dragon. He really was the softy that her first impression told her he was, even though he was quite the stern teacher it was clear that he wanted to help her improve and was quite attentive to her. He increased the strength of his blows to the point that they hurt, but without doing any real damage and often asked if she was doing okay.
'I'm looking forward to working with him. Maybe I should teach him a few things too?' Cherry thought, heading back to her and Robin's room.