Powers & Abilities Mera Mera no Mi considered to be...

[NotTommy]

I mean Entei was pretty crazy, and even before then Ace had demolished tons of ships in one hit. Not surprising to see this reiterated in supplementary material.

 

[matt245]

I don't know man, i'm pretty sure being completely enveloped in a fire ball for many minutes would make a dent even in the best haki user; this goes for all logias by the way: when Aikanu literally turns the ground into lava for miles around you, how much time will your CoA buy you, if you can't fly?

With a CoA good enough you should be able to counter it pretty easily seeing how pre TS characters dealt pretty decently with both fire and magma. Worst case scenario you'll have to use ACoC which should protect you 100%. After all, haki rules above anything else.