What could it be ?
I really couldn’t find any clue about this national treasure,so i will say my opinions
Some say it is eternal log pose to Raftel..which is stupid because then why don’t World Government take that and go get it,some say it’s location of One Piece,again it’s weird.
Some say it’s key of Uranus (to use Uranus you have to have a key) or even Uranus,which might be,but still we don’t know anything about Uranus – some say that Uranus has teleportation power,it could be,but Uranus has to have some powers that can destroy the world,so maybe with that key it could teleport you anywhere and destroy a lot
Anyway let’s start with Celestial Dragons..why are the people afraid of them and why does the World Government even listen to them..they’re weak and useless..but what if it is not the case and they don’t listen to them because they are descendents of creators of WG..what if they posses some kind of weapon that could easily destroy the world
That national treasure could also be Egg Roger had,but i doubt that because that would mean he had to get it on Mariejois and Gorosei would probably attack him and he would die
Which leaves me now for the last opinion..Tree of life
We already saw Tree of Adam and Tree of Knowledge – and it’s said that Trees in Eden are Gods treasure – his garden..also Tree of Adam is called Treasure Tree of Adam
Tree of life grows fruit every 10 years and when you eat it,it will grant you immortality.
Doflamingo knew about this and used it somehow to escape from Mariejois – he said he would destroy the tree if they don’t let him go away – there was no fruit on it so he couldn’t eat it from it,my guess is that he returned to Mariejois to eat it and gain immortality,but he failed(he also asked from Law for immortality) – also he said when people find out about this it will shake up the world – when people find about it everyone would try to gain the immortality,which would cause chaos.
– fruit to live 1000 years
It’s said that National treasure when used with Ope Ope no Mi could grant the ability to destroy the world – Ope Ope no Mi is one of the devil fruits which reduces persons life – with that tree,user could use Ope infinite time without dying which would be crazy strong – i think Ope Ope no Mi is first devil fruit to be ever created and originally was supposed to be used with Tree of Life.
Also Tree of Life is a forbidden tree – no one is allowed to eat from it.
Gorosei are immortal because they ate from the tree because to World Government they represent Gods.
The devil would be the “D” and they tried to tricked someone to bring them that fruit.. that person was Joy Boy.
But instead he ate from the tree and returned to “D”‘s and said he ate it,so D’s made him their king..king of ancient kingdom – in this case D represent the Devils and Joy Boy represents the Eve and my guess would be Joy Boy had a brother who represents the Adam – Joy Boy is younger one.
Now God was angered and he wanted to banish them from that world – Gods(WG) tried to kill Joy Boy(note-war didn’t start because of the tree,war was lasting even before that),but it was impossible and war was lasting too long and Ancient Kingdom decided to make weapons – Joy Boy was smart,they used it and had more chances of winning the war,but something happened…Joy Boy’s brother died..or he thought so..which made Joy Boy have feelings like he doesn’t care anymore and it made him lose the war and the result would be everyone he knows death..
Joy Boy later apologized to Poseidon for failing and that it was his mistake that his emotions overtook him..and Joy Boy was captured and is still held there somewhere by Gorosei,but before he was captured he made another weapon that would revive everyone who died because of him..but he couldn’t use it,he didn’t have the last piece of it, the One Piece.
As i said his brother was dead,but he wasn’t actually,he was captured and he escaped..later he also ate fruit from the tree and hid himself on the island called Raftel and he is now there protecting the weapon created by his brother and Joy Boy’s brother is the Rio Poneglyph and he created every other poneglyph – except Joy Boy’s one –
Roger could’ve used the weapon to revive everyone,but it would only cause WG to find out about location of Raftel and it would cause another war which would result in death of everyone,again – first he needed to find every ancient weapon,but he didn’t have every one of them and to find every other ancient weapon it would take him some time,which he didn’t have
I believe Luffy will find one of the ancient weapons,but as he is reckless he will revive everyone from the ancient kingdom,which would cause huge war..later Poseidon will come which would be second weapon and if Elbaf theory is true – that they have Uranus ..they will come too with that weapon
Ending of One Piece will be Joy Boy apologizing to his people and thanking Luffy
and there will be a black screen that will say 500 years later – Usopp telling the stories to kids
Sorry for the long post..i hope you liked this,if it makes any sense..and also tell me what you think that Mariejois’s National Treasure is
*Theory by Doctor Room