The Numbers

[SSJ2]

First of all, what the hell are they? They look like a hybrid of Oars and a giant.

There isn't one person in the entire alliance that should be able to fight one of these beasts. Oda is continuing to make the alliance's odds worse in the upcoming war. I'm not sure why these needed to be introduced lol

 

[Captain Cadaver]

Considering their horned appearance, weaponry and notable drinking problem, it could be that they're members of the same race of giants as Kaido, with their appearances possibly being from their hybrid-Zoan forms (assuming they're Smile users).
Considering they're suggested to be not directly a part of the Beast Pirates, it could otherwise be that they're giants native to Wano, considering they were said to be in Onigashima (though it's unclear if it meant native to or stationed there) and the name of the area would be fitting for such creatures.