I would suggest Flamekin, but that's the name of one of the units in MY fire demon army.
Do you wanna see them, just for reference? I haven't ever actually used them, they're still a combat-virgin army. So really they're just for show.
Here, I think once the PW forums are up and running again I'll post them as a free army for everyone to use. I don't want them to go to waste.
You can have the spritesheet for inspiration.
The first unit is the Flarekin (smallest), then Flamekin, then Firekin, and then Demonkin (the biggest one with actual fire and stuff).
(click for better quality image)