Sophie of the Blooming Boomers
From the current lore document -
Sophie has long blue hair, and a penchant for incendiary devices. She's so obsessed with explosives, she's been known to explode herself if she overheats. She rarely makes a league appearance in any capacity without disintegrating, whether she wants to or not.
She's a regular at any car racing event, but the bets aren't usually around where she places. They're over/under bets on how long until she explodes and dusts the track.
She can't actually produce fire, but since
Samarkana drew the little fireball in it would make sense if she's a bit of a pyro. There's a decent chance she's worked on making herself explode on purpose too. If you get angry enoguh to explode that often, might as well make lemonaide and become the human explosions and fireworks expert. On top of that, she's come to enjoy the release blasting herself apart brings. Whether or not her friends appreciate the resulting fireball is another question.
How does Sophie leverage the ability to explode in matches? Carefully. Without a team mate to restore her ashes, it's not a great idea, especially if the opponent can just run away. But it's definitely a flashy ability, and it has given her a following.
(That's me)