So basically I have a simple question. I was thinking about using Lightning as a very significant element in my game, and here we go: Would that could as fire?

It is a similar question like that already asked: "Is it appropriate to use magma as fire and ice as water?" I allowed those two but I'm not so sure about the lightning.

Fire, by definition, is a chemical reaction involving oxygen.
Fire, by archetype, are bright orange flames causing heat and light.

Lightning does not fit any of these.
But still, lightning is cool. Perhaps lightning could cause wildfires? Or cause the targets to burn?

I'll let the community give its opinion on this but I don't think lightning is sufficient.

Ok, thats cool. I was thinking they were quite similar in the visual aspect, both being caused by light-emitting superheated air. At the very core though, yes you are correct both are quite different. Now I wonder if I can make something between them for the purposes of my game :)