Theory Vegapunk's ally is Daiamondo Jozu

#1
Remember Doffy's playing cards seats? Heart Seat: Corazon, Spade Seat: Pica, Diamond Seat: Diamante, Club Seat: Trebol
I believe that Luffy will have a group that fits that theme aswell: Law is captain of the Heart Pirates, Ace was captain of the Spade Pirates, Barto is captain of the Barto Club. Not sure who the fourth will be. Either Bonney or Jozu. Bonney because she is called Jewellry. Jozu would fit also. Even more so if he started the Diamaond Pirates in the mean time. Ace got executed, so I think the other three will get caught by the navy soon and set to be publicly executed.

Jozu being Vegapunk's ally, and getting captured in the process of saving him, would fit well with my idea here. Also the Transponder Snail has a weird upper part, that could be diamond like. Jozu is hiding after his side lost the Payback War. He could have looked for Vegapunk to get a robot arm or something. Obvoiusly Vegapunk would keep it a secret, as he is a wanted man. Maybe Vegapunk wanted to recreate his Devilfruit.
 
#5
he is someone who has a position in WG, & since we saw Garp speaking in a den den mushi, just like VP ally, so if that was a hint, then that person could be Sengoku.
Garp speaks to Doll, & Sengoku speaks to VP.
 
#6
Don't think Stussy is it, so it could still be Jozu. Here are some additional reasons for why he fits:
-Last arc, Nekomamushi had an ally too. It turned out to be Marco, a WB commander (Jozu was one aswell)
-Jozu's crew fell apart and he is hunted by both WG and BB, he needs a hide out
-If Jozu was there, Vegapunk could have studied his fruit and replicated it for a seraph (S-Hawk most likely)
-Jozu lost one arm, Vegapunk could have made him a mechanical replacement
-When Vegapunk asked the ally, they replied that they were waiting for such an order. Jozu is a stoic obeying man. That is exactly how he would respond
 
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