How did Fuji-chan become an admiral? And secondly, how strong is the strongest vice admiral (sans Garp)?

[Warmmedown]

How did he become an admiral? He wasn't even a marine until during the timeskip. So he joined and immediately became an admiral, but who promoted him? His morality doesn't seem very aligned with Fleet Admiral Akainu, so was he promoted to Admiral by Sengoku?

If he was promoted despite having no marine experience, does that mean he's way ahead in power than the next most powerful Vice Admiral (sans Garp). Or was he promoted for some other reason?

 

[SSJ2]

It was said that the Government held a conscription event after Akainu was promoted and Aokiji quit. Fujitora and Ryokugyu got the vacant positions.

Maybe Akainu wasn't the one who decided on the positions, it might have been Kong who is Commander in Chief. I'd wager it was mostly to do with power though, as realistically, how many people can have Admiral level strength? The interesting thing with Fujitora is it's hard to tell if he has had his Devil Fruit for a significant amount of time. On Dressrosa he was using it clumsily and as if he was struggling to control it, which would imply that he only obtained it recently. If that were the case, Fujitora somehow got to that level of strength even without a Devil Fruit on his own. Pretty impressive really.