Sabo vs Akainu seems likely to happen in the Final War since Sabo is more fit to avenge Ace than Luffy now that he has the MMnM. Besides, Luffy will be as strong as Roger or maybe slightly stronger EoS so his final opponent sure as hell isn't going to be a FA level fighter.
As seen in Ace vs Akainu, orange/yellow fire isn't as hot as magma and has no effect on a magma person.
However, in this clip blue fire, which is hotter than yellow/orange fire, doesn't get burned and doesn't burn magma.
[video=youtube;aBP1rcU2VIU]https://www.youtube.com/watch?v=aBP1rcU2VIU[/video]
Blue fire is as hot as Akainu's magma so Sabo will learn to use only up to blue fire because if he learned white fire than magma would have no effect on him and he would stomp Akainu. So he will learn blue fire, which is on par with Akainu's magma, nothing more nothing less. Also, blue fire would look really good with Sabo's design.
As seen in Ace vs Akainu, orange/yellow fire isn't as hot as magma and has no effect on a magma person.
However, in this clip blue fire, which is hotter than yellow/orange fire, doesn't get burned and doesn't burn magma.
[video=youtube;aBP1rcU2VIU]https://www.youtube.com/watch?v=aBP1rcU2VIU[/video]
Blue fire is as hot as Akainu's magma so Sabo will learn to use only up to blue fire because if he learned white fire than magma would have no effect on him and he would stomp Akainu. So he will learn blue fire, which is on par with Akainu's magma, nothing more nothing less. Also, blue fire would look really good with Sabo's design.