This hero doesn't exist in Bug Heroes, but I, K-leb25, have written this up on Possible Updates for Bug Heroes as a suggestion for a hero. This page contains full detail on him.
Description: This guy loves to light everything in glorious...light. His habit of lighting came from the fact that Fireflies...light their abdomen at night. Helping him with his mischief is his Flamethrower, a master weapon effective at burning every little bug in sight. Unfortunately, it is highly ineffective to kill armored enemies. Firefly has a nasty habit of burning even his own kind whom don't fight for the right people. His weapon, though, proves useless against killing the scorpions, so he joined the Bug Heroes to see his dream come true. In-game, he is the ultimate early-to-mid killer, as his short-ranged flamethrower will make quick kebab out of the small enemies. He has only 500 health, with no armour, yet is quite fast for a heavy fire-power hero and also flies. His weapon blasts balls of fire every half a second, which disappear shortly after being fired and do 20 damage. They do expand quickly, making a good AoE. The weapon's in-game description is: "This weapon quickly fires flames that disappear shortly after. But, they sure can burn those fleas." One of Firefly's most unique traits is that at night, he instinctively lights up, gaining 25% more speed. This can be upgraded in his level-up skills:
Health (increases health by 30 and heals by 60), Speed, The Light (increases speed by 25% and damage by 20% when he lights up) and Fiery (increases the AoE of his flamethrower).
His weapon can be upgraded to a Mega Flamethrower, which increases the damage to 40 and the time the fireballs last for. "Fry Fleas, Cook Cochroaches, or make a fire for the camp. This can do anything!" Then, there is the Plasma Pulsar, which increases damage to 75 and allows for piercing a lot of armour. Upgrading his weapon first is a necessesity for him to be useful mid to late game. "Rock has been melted to such a degree, that it forms a gas of "pierces all armour." A nifty weapon indeed."
Ward of Flame-- the ability is that Firefly lets out a gust of fire, which blow on a specific area. Then, for 30 seconds, fire starts burning over that area, slowly spreading. The fire does exceptional damage to the weaklings (10 damage every 1/4 of a second). It costs 800 and has a cooldown of 90 seconds.
Fire-Charge-- Firefly charges in the chosen direction. If he hits an enemy, his flamethrower will blast out flames, knocking back the enemy if small or medium and leaving them distracted by being on fire for 10 seconds, doing 10 damage every half a second. Grubs, however, don't get distracted, but still damaged. It costs 600 and has a cooldown of 60.
Circle of Fire-- Firelfy spins around will bursting out fire. When he finishes, you'll realise he just made a circle of fire around him, which does 10 damage every 1/4 of a second for those in it. Firefly can hardly move, because trying to fly over this fire can badly damage him. This is very useful if there are onslaughts of melee troops, because if they go near you, they'll be burned! Be careful if there are many ranged untis around, though. It costs 800 and has a cooldown of 90 seconds.
Burner Pack-- Firelfy wears a special backpack, giving him the passive ability of increasing the speed of his flamethrower. The ability is that his flamethrower pierces armor for a short time. Very useful for coliseum. Costs 1000 and has a cooldown of 100 seconds.
There is more to come! Please leave a comment to say whether he is under or over-powered!