Me too XD I want to write (even create my own manga!) my own series XD and also, as it looks like, my main would be using fire (then he'll learn lava and magma and shit)
About the abilities, I am still thinking things like:
Liquid Fire (fire that can be buttered up by water)
Heat Wave (burning enemies stray too close to the user)
Body Heat Based Genjutsu LOL (i think this is bullshit but i really want to make this, the user will control enemy's body heat by lowering or raising it, making them hallucinate or something)
I call this one Hinotama because of that weak Hinotama Soul card on YuGiOh! (this is just like a homing missile, it will follow ur desired target)
and the ability of heal wounds when on FIIIIIIRE! (or when bathing at magma)