One of the most top rated character and dearly missed, Portegas D. Ace, the late brother of Luffy and Sabo, commander of the second division of the Whitebeard pirates, son of Pirate king, Gol D. Roger and the first known eater of the mera mera no mi (flare flare fruit) and became a fire human.
Second contender is former Navy Admiral Aokiji (blue pheasant), the ice human whose real name is Kuzan. The second top rated of all the Admirals (after Fujitora, as polls show).
Aokiji throw a chilling ‘pheasant beak’ (that move he made after ace and luffy at the marine ford war, don’t remember exactly if that’s the name though). Ace with a neat smirk on his face, throws a blazing “firefist”. As both attacks cancel eachother, Aokiji throws a few number of “ice spear” (ones he threw at whitebeard before freezing the bay). Ace uses “flame pillar” to protect himself.
**Aokiji realizes that he’s at a slight disadvantage when it comes devil fruit elemental power and decide to do close combat, creating an ice sword cladded with haki and charge at Ace**
Ace fires off two of his 'fiery spears' but kuzan went mid-air to avoid the attack and tries to cut ace with that sword, which misses and froze the ground, and a gigantic ice berg was created. The smiling ace now realises that aokiji doesn’t plan on giving him any room or time to counteract, so he catches the sword with both hands to melt it. Aokiji quickly made use of this opening and deliver one devastating blow to the stomach. Ace finally got some room between him and aokiji, but aokiji turns the entire environment in an icy frozen landscape. As he melts the ice few feet around him, ace create a giant “entei ”.
They were both beaten by the same man, Akainu, whom possess devil fruit powers they’re both inferior to. Before attacking luffy, he stated to ace that he has the power to burn even fire, so there’s a huge gap between there powers. Likewise any well thinking man can agree that fire is superior to ice, to some extent at the least. So ace wins when it comes to element/Devil fruit. Aokiji did fought akainu for 10 days, but ace fought Jinbei for at least a week when he was trying to kill Whitebeard. So as they both got stamina to spare, so it’s a tie in this area. As it regards to combat ability, from what we’ve seen ace excel in hand to hand combat, but none the less, I doubt someone can become admiral solely just because of their devil fruit powers, there has to be combat ability to back that up.
Side note: We know fujitora is a swordsman, and We’ve seen kizaru display swordsmanship against Rayleigh and akainu shows he got hand to hand combat ability in his fight against whitebeard (RIP pops)
I could be wrong though, but judging from the animation, ace supersedes in taijutsu. Lastly, just the same as I don’t see ice beating magma, it don’t see it beating fire either. So ace gets the win.
Winner: Portegas D. Ace
~Please note, the battle scenery is mostly fictitious as we’ve only seen both characters clash for a brief moment in the marine ford arc. Thus most of the battle is based upon imagination and opinion. Your opinion might differ, and I respect that, please respect mine.~