Fire I, Fire II, Fire III

[AshlikeSnow]

Well others have explained that -ra means second and -ga means third, or something along those lines. So it kinda makes sense for us to call it Fire II and Fire III.
Personally, I want to adopt the French way. "Extra Fire, Mega Fire, Giga Fire!"

No that is incorrect. The "a" and "ga" come from the Japanese kana writing system which "a" is the vowel and "ga" is a consonant followed by a vowel, this does not translate to 1,2, and 3.