Who is this Admiral?

[SSJ2]

http://onepiece.wikia.com/wiki/Ryokugyu

Also how did he and Fujitora even get appointed to Admiral as the were not Vice-Admirals prior.

 

[Kyo]

There was a draft or something...I don't remember exactly. I think he wasn't in the military prior but once he got in he was already eligible.

 

[SSJ2]

I recall a draft being mentioned now as well. That's retarded imo. How do you just draft a random person with no affiliation to the Marines to the highest rank?

 

[sei'taer]

I'd assume it was devil fruit related

 

[Alex Boss]

That is Green Bull.

He is the new admiral we haven't seen yet.

 

[Yoshi]

To be fair, all the Vice Admirals besides Garp are poop.

Yeah, Doflamingo mentioned Fujitora being drafted into the Marines. Him and that other guy being drafted to Admiral position is likely due to their devil fruit abilities, assuming they had them prior to their promotion. Controlling meteors is crazy, although even that couldn't destroy the birdcage.