I dont think its going to be blackbeard, we know Auger was with Kuzan, and the battle for law vs bleackbeard has not been reached yet even though we know how this will end for Law. We can only narrow it down just a little bit and I am hoping its not Burgess again.
Yeah I was hoping it would be Shiryu at least, maybe Lafitte too? It begs the question where they are, what they've been doing and who is remaining behind on Hachinosu and guarding it too. Given his size, San Juan Wolf must be at Hachinosu at least?
I'll be legit mad if its Burgess too haha. Maybe Devon might show up and impersonate one of the Punks or Stella himself? Or even worse Kizaru or especially Saturn? She overrides the Seraphim to the BB pirates side, whilst pretending to be Saturn?