Fire I, Fire II, Fire III

[Nestama]

They thought "Fire/Fira/Firaga/Firaja" would confuse people who aren't japanese despite the fact that we've been used to them for decades. The game's dialogue is supposed to be less confusing and a little more racy as well, but the english localization team refuses to cooperate, even when called out.

All the other localization teams fall in line.

To be fair, it was mostly for people completely new to the Final Fantasy franchise (and the -ara suffixes didn't exist in English until FFVIII came out).
German uses suffixes (Feuer, Feura, Feuga, Feuka), but French go in a different direction. Feu, Extra Feu, Mega Feu, Giga Feu.

What's interesting is that Astrologian, in all languages but Japanese (they still end with ラ), go by Roman numerals. So Benefic II, Malefic II and Combust II also end with II in German and French (unless xivdb is wrong).