I know I would be hella scared of all 
if I got barbecued alive once.
Just imagine:
You run into a terrifying, skilled, strong, and mysterious enemy who could totally wipe out entire armies and scrub your face on the floor—
You use your last shred of power to conjure a small, simple, beginner-tier fireball.
And the guy runs away from you screaming like a banshee.
Yeah, that’s how my dear ROs will recognize my MC before the mask even comes off. 
Honestly, any other characters in the story who knew how the MC died should avoid lighting a marshmallow on fire nearby or risk getting their head whacked. PTSD is a real double-edged nasty.