[quote=@Caits]
Yeah butnnatsungetd sick when he eats stuff other then fire, however, he has then been able to using a combo of Fire-lighting and iron-fire, but I suspect this is because Laxus and Gajeel are dragon slayers too.
[/quote]

actually natsu is able to use the lighting-fire magic because he devoured a special type of lightning magic used on him and it just kinda stuck around in him.