I also think that sanji is some tenryuubito, but i remember what they did to flamingo, they never accept him again, so maybe they are not the reason why they need sanji alive, they dont want someone that will disgrace them because sanji is a pirate.
So my second guess is he has something, like secret or weapon that is very important..
I miss sanji~ >. <
*sorry for my bad english! >. <
True they didnt want Doflamingo and his family back but its because their father resign from being tenryuubito. Maybe Sanjiis circumstances were different. He could have been kindapped when he was small
Or his familly was the most important in the Tenryuubito and they had plans for his life but he had different ambitions such as to become the best chief and as we all know Tenryuubito had slaves so he couldnt do it and ran away. But his father maybe want to force him in doing what he says so.
There is so many possibilities .. Oda sensei please just tell us who is Sanjii please ! I have so many ideas about Sanjiis background but i want to know what you planned for us ! :? :)
I believe no strawhat could be a traitor, never.
It's a blasphemy! ヽ(`Д´)ﾉ LOL
(seriously) I mean; anything could happen in One Piece, but we have to be faithful to nakamaship.
How about if Sanjii is actually one of the ancient weapon xd you know like mermaid princess is Poseidon.
But honesty there has been alot of traitors in straw hat such as nami with arlong, robin with CP9 and Usopp with his ship. But they were all traitors because they didnt want anything to happend to their friends, so its possible that Sanji may betray them cause he will hope that this way he could save them ... dunno but Oda senseis style is for mugiwara crew to betray each other in the name of friendship xd haha so we can expect anything.
You are right... but I wish it wasn't the case. I like to believe that they have built a stronger trust, specially after those events. They should realise that fighting together is better than fighting alone.
I think he must be part of some tenryuubito family because they are the only ones who would have this kind of power to announce pirat to be wanted alive only. Even princess Vivi had to hide the fact that she had anythinng to do with the straw hat pirates .. and Sanjii is officialy one of their crew member so if he would be some random prince there would surely be no problem to kill him.
Or my second opinion but im sure its not possible because of the bond they have with each other but I just tought of it that maybe .... - Sanjii is a traitor and is secretly working for the marines thats why hes wanted alive only.
My third quess is that he knows/posses some secret very important information thats why they dont want to kill him.
Or maybe he comes from some kind of clan where their blood have some special power and everyone else died except for him so thats why they want him alive haha xd but i prefer my first version... i hope he is a son of some tenryuubito xd that would be the most interesting from all my options xd
Oh yeah Sanjii where are you ?? :)