@Ivotas:
Well so far it appears that Oda is following the order of the solar system when he introduces the Ancient Weapons. He started with Pluton which would be the 9th planet of the solar system. Poseidon has been made to Neptun in the roman mythology…the 8th planet. The 7th would now be Uranus (german spelling).
I´m curious to see whether or not the third Ancient Weapon will in fact be named after it or not. Could be, could be not. Only Oda knows for sure!
@songo1:
Hello guys, glad to be here. I'm rather new to this forum but have been keeping track, especially of this thread. This is my first post too, hope you like it.
That aside …
I noticed that explanations for Uranos only established that he is Father of the Sky, but further mythology connected to it becomes ambiguous trying to connect with OP world. Don't get me wrong, it was starting point for me too. As I read more and more about sons castrating... nothing new was there, but in process found something interesting... what are the planets meaning in astrology. Apparently Uranos is associated with new and unconventional ideas and beginings of industrial revolutionary changes. Not only but also pregressive ideas and in the societies relates to radical ideas (people) or events that shatter the "usual" order of the world.
As reading this only one come to mind, the entire story of OP is about this, especially this Ancient Kingdom. Personally, I think this might have sth to do with Dr. Clover report especially with words "...the key is this kingdom name", although right now this far fetched.
I actually find the astrology theme much more interesting than the greek/roman mythology theme (even though they are connected, both might as well apply). Not at all familiar with astrology, but after reading that post I googled about planets meaning and found some very interesting links, that fits very well with the OP universe and the ancient weapons in particular. This one I find best describing it, although they all says more or less the same, some goes more in-depth with the zodiac signs etc..
What I like about this theory is how well the themes represents the 'force' who will use it (just my conclusion of the theory, we haven't really much clues as to it will turn out.) At the top o the page there are two sections not hyperlinked, Planetary Associations and Things Governed By Planets. Both sections connects each planet/weapon to it's user very well.
Starting with Poseidon (or [Neptune](http://www.trans4mind.com/personal_development/astrology/LearningAstrology/theplanets.htm#o9 Neptune) in the planetary system) as we know most about it, it very much describe the incidents of FI.
It's described as the Planet of Illusions, also associated with dreams.
It says the keyword is refine, which fits both Queen Otohime's and Hody's causes. Otohime's good cause of refining everybody's mind from hatred amongst each other, Hody's cause of refining the world from humans.
Transcendence and delusion obviously fits the New Fishman Pirates very well, thinking of themselves as gods and a superior race. Not to mention the association with drug abuse.
Both Queen Otohime and Shirahoshi went as far as to sacrifice themselves, although Shirahoshi did it for her people rather than her ideals and got saved, while Otohime sacrificed herself for her ideals (and ultimately her people).
Pretty much everything in the governed section fits the theme of FI, and the qualities of Neptune, transcendence, higher faculties, psychic abilities, sensitivity does fit Shirahoshi nicely too.
…this took longer than I thought, mainly 'cause I've read and reread a lot to come to the conclusion, also changed my mind about some things in this theory. At first I had some thoughts about which civilisation used the weapons in void century, and who would use them in the final war. Now I don't really know, though I'm still using the astrology theory. Too tired to continue with a full analyse so i'll just haste through the rest.
I'll add http://www.astrology3d.com/planets.html as another source since it deals with zodiac signs and elements of the planets too.
Poseidon has the element of water, controlling the Sea Kings. Clues point pretty much to her being Luffy's weapon in the war.
[Pluton](http://www.trans4mind.com/personal_development/astrology/LearningAstrology/theplanets.htm#oo10 Pluto) also has the element of water, being a battleship. Highly destructive power, maybe nuclear. It would fit WG due to the part of Plutos secret nature (Pluto's secrets are also secrets of the mind. Areas where we might have hidden shame or guilt, the skeleton in the cupboard.) Fits well in with the void century part. Also the conflicts within WG that has only been touched, but I'm pretty sure will unfold much more later on.
And last, [Uranus](http://www.trans4mind.com/personal_development/astrology/LearningAstrology/theplanets.htm#o8 Uranus), element of air. All the mentioning of revolution and it being called the Planet of Revolution, well, Dragon and his party. Could be weather related.
Sort of the basics of the theory, checkout astrology for more deep analysis. Probably some fallbacks, many of the characteristics could very well fit to others, like Pluton and BB, with all the dark power in it, Uranus and Doflamingo with his chaos thinking. I've seen a few theories about Enel and Uranus and some stuff actually struck to me as him joining the Revolutionaries, being the description of Uranus linking to both of them.. but I don't find that thought very plausible. If the weapons would actually be divided to three factions, I'd go for the ones stated above. Mainly because the final arc will most likely be a big all out war with WG, Revolutionaries and pirates clashing. Luffy will in my mind already have defeated BB before that and go to war as Pirate King.
Another issue with this theory is the whereabouts of Pluton, leading to another theory. Luffy (or at least Robin) knows about Poseidon, Robin knows about Pluton and will most likely find out about Uranus. Also, though I'm not sure of this, but if Franky did memorise the blue prints of Pluton he could build another one as well, though i doubt that. Point is, Luffy might actually get two of them, perhaps even three. I can somewhat see that happen, considering the sheer amount of military the WG is probably building up now under Aikanu's regime and BB collecting every Devil Fruit he can find. Perhaps Luffy and his allies need all of those weapons to actually stand a chance?
…ok, didn't haste that much after all, though I did have more on my mind at the beginning. But now I'm actually just leaning toward the weapons being based on astrology rather than gods, or a mix of both. Not at all certain about any conclusion anymore :) As how it should be, I enjoy much more when I'm surprised so even if there is some substance to these theories, i do hope (and know) Oda would go at it in another direction. But a discussion just for the fun of it would be cool anyway. Peace out!
(Also, kudos to Ivotas for actually predicting the name of the third weapon 7 years ago ^^)