I recently saw some theories about Shanks’ full name so I just stumbled upon a thought that Shanks and Ace might have some family ties.
Shanks’ Full Name – Shanks’ full name is… Portgas D. Shanks, so he’s Rouge’s brother, Ace’s uncle and Roger’s brother in law!
Why do I think that? Here are some elements that make me think he is a Portgas:
-He tried to prevent Ace from pursuing Blackbeard by asking Whitebeard to call him back, but why? Ace isn’t one of his Nakama and he should not worry about a member of a rival crew. Maybe because Ace presented himself to Shanks as Luffy’s older brother and he was thankful that he took care of him, but that’s also possible because he is his nephew.
-What was Shanks doing in the Goa Kingdom? He’s from West Blue and there is nothing really interesting to do in East Blue for a pirate of his caliber, I can see him coming to see how was doing his sister’s son and then he met Luffy during his journey there.
-He stopped Kaido from reaching Marineford to let Whitebeard and his crew fought the Marines to save Ace and then came to put and end to the war, that was not really his problem, why did he so much to help save Ace? He also asked Sengoku to let him make a burial for him (and Whitebeard that he respects ), possibly in memory of his sister?
-Ace was born in Baterilla, an island in South Blue, but it is not stated that Rouge was born there, she possibly be from West Blue like Shanks and went there to have a peaceful relation with Roger.
-A less important point is when I look to the drawing of Portgas D. Ace at 40 and 60 that were made by Oda, I personally find that he looks very much like Shanks with black hair (like his father) but that’s only my opinion!
-I also don’t see Shanks coming in front of Ace telling him «Hey I’m your uncle», he’s really mysterious as we can see recently by his strange relation with the Gorosei, that could be also why the Government respect him, he had a relation with Roger but he’s too powerful to take him down so they prefer to have a «good» relation with him, and he probably knows what happened during the Void Century (even if he hasn’t been to Laugh Tale) so they prefer not to anger him.
These are elements that are certainly very easily counter-able but I think it is plausible and I think it could be pretty cool. By the way that’s just a theory, so let me know what do you think about it!
*Theory by Traffy124