Seeing now in context Dragon’s reaction it becomes quite a big deal. If he wouldn’t know about Drunken Iron Ogre he could have just said “no” but he didn’t address the question at all. Meaning there is a deeper secret behind it that can’t even be hinted on or it would give too much away. Another hint is extremely subtle and requires some follow-up questions to properly conclude.
Dragon is planning to meet Luffy one day. Why though? He obviously cares for his son and is pretending to not know him even when he obtained a 300 million berries bounty. So he wants to protect his son by not tarnishing his name with his and wants to make sure Luffy can fulfill whatever goal he has, even if it’s a 99% death scenario like the road to become Pirate King. Safety is not the issue for Dragon but the mission itself is what is important to him. Why would he not meet his son now if he wanted to meet him? Luffy’s name is beyond repair and there is no cost for Dragon but he believes that they will meet one day eventually even though he is not planing to meet him himself anytime soon. Maybe his first visit to Logue Town gives us more insight into his mission.
Dragon was on Roger’s death day in Logue Town, that seems almost like a ritual to me and that he comes every year, showing that Roger is extremely important to him and his goals. The chapter title is “the legend has begun” and Dragon remembers Roger’s words in his head and replies to them thinking if the sentiment applies to Luffy. The response is “A pirate? That’s fine, too…” and he grins right before he meets his son. Dragon knows Luffy might be on the path to fulfill the “Will of D” (which Roger’s quote literally is, read my “The First Storm” theory if you doubt this and are interested) and is making the connection between Luffy and Roger himself(thinking about Roger’s words and seeing how the values of “D” apply to his son). Now we can answer why Dragon knows that his son will meet him one day. Because the path of finding Laugh Tale and becoming Pirate King requires one to find all Road Poneglyphs.
One has been missing and for some reason Nekomamushi and Inuarashi don’t know where it is, even though Roger has discovered it to find Laugh Tale.
There are two more points that I want to raise. The first is related to Dragon’s tattoo and what it could mean symbolically.
Like prior stated, we can ignore the lines and have to focus on the 3 red cubes that are visible on his face. One could be hidden under the chin but if we keep the mystery of the Road Poneglyphs in mind this should sound familiar. Dragon has 3 Road Poneglyphs marked outside of his body and the 4th is missing, hence why it isn’t shown. 3 are in the open and the last is hidden, sounds exactly like the kind of confirmation that we are looking for. The person who holds the 4th Road Poneglyph has the mystery of them marked on them in exchange for the hidden knowledge. Or if we go less extreme, out of duty for the cause Dragon has inked a visible tattoo on his face for the world to see but only the knowing will understand its meaning. Only someone who is on the journey to find all Road Poneglyphs and Laugh Tale will have a reason to meet the man. Especially if you have gathered 3 already and are in search for the 4th one and see someone of Dragon’s caliber having 3 red cubes on their face. Let’s finish this theory with a bang. You won’t believe which cover page was shown when the Road Poneglyphs where introduced for the very first time.
I can’t even remember a single cover page of Dragon prior to this point and he makes an appearance(correct me if I am wrong because it doesn’t break the case but would just make it even more stunning) when the “new” Road Poneglyphs came into play? This is not only suspicious but a giant red flag that Dragon is connected to the Road Poneglyphs. His tattoo symbolizes the mystery of the Road Poneglyphs and that one is not on the outside but on the inside. To find Laugh Tale one must meet the keeper of the last Road Poneglyph, the dragon that guards it.
*Theory by Donal D. Trump