Well, I'm going to make a bet that this Wergo/Vergo guy is part of the WG, apart of a secret operation allowing Ceaser to continue his experiments to see if he can do anything of interest or help for the WG. And this Joker guy is the head of the operation. If not, then he's definitely apart of some elite pirate group, possibly Yonkou, but I doubt it as it doesn't make much sense. One thing is certain, which is, this Wergo guy is quite powerful to be allowed to roam alone in the New World without any sort of back up.
So Wergo is able to cause Law quite a bit of trouble without even touching him. Law spits blood, falls to the ground, can barely stand up, and then with one powerful hit gets knocked out. Interesting. I don't want to say it's CoC haki as of yet. I've never seen an outcome where the victims hit by a CoC haki-blasts causes blood to appear. Although it could be possible, why not?
And we are unable to understand as of yet why Luffy, Smoker, Tashigi, Franky, and Robin were all knocked out. Again CoC haki-blasts were out of the question, but we are taking the word of the fodder-marines. Interesting, but a little weird for someone like Luffy to be taken out by CC.