In use by 2490, the hellion is a high-speed raider built around a lightweight four-wheel chassis. Hellions are capable of causing damage disproportionate to their size, particularly against enemy infantry, thanks to their heavy Infernal flamethrowers. Additionally, their remarkable acceleration allows for improvisational tactics in the field. Some hellion drivers will deliberately outrun their enemies only to turn and attack when they have reached maximum range. The low cost, exceptional agility, and devastating firepower of these vehicles have made them extremely popular with mercenary companies.
Taking note of the hellion's good performance record, the Terran Dominion developed the hellbat, a vehicle based on the hellion, but with the ability to transform into a bi-pedal walker.
The hellion is a replacement for the vulture, albeit retaining the firebat's abilities.
The hellion has movement animations; it slightly rises when it starts moving, and lowers when it stops.
The hellion is a fast-moving unit, fast enough to chase down enemy units and easily reposition itself. Hellions are strong against tier 1 units and workers. They are weak against thors, stalkers, and roaches.
The Hellion's weapon targets only ground units. It does splash damage in a line, targeting one unit but striking all units along the line.
The attack is well-suited to destroying weaker units such as marines.
The hellion must stop in order to attack. The weapon strikes targets instantly and can be used for (almost literal) hit and run attacks and "kiting". To do maximum damage, it should shoot once, close the gap, shoot again, close the gap again, and so forth in order to maximize damage and not waste shots. Attacks should not be targeted on the closest opponents, but instead those further back, to ensure the maximum number of enemy units are hit. If the attack is launched at a precise distance, then by the time the flames hit the target the Hellion can be moving away to safety. However, units that move out of the flame take less damage so a player should try to keep the flame on enemy units to maximize damage.
A recommended tactic is to use the hellion as an ambush unit, positioning it on high ground to attack units below it.
4 Hellions (ideally upgraded) can be loaded into a medivac dropship for a tactical strike on the enemy's mineral line.
Though delicate, hellions are agile, making them excellent hit and run units in the early game, particularly against melee units such as zealots or zerglings.
A factory can immediately produce hellions directly, and if an armory is present, can also produce hellbats directly. They cannot switch forms into each other unless Transformation Servos are researched at a factory tech lab.
Dustin Browder has expressed regret about the handling of the hellion in the campaign. While the hellion's mobility is useful in multiplayer, firebat/medic combinations in singleplayer arbitrarily outshone it.
A civilian version of the hellion, with flame paint, was to be available in the single-player campaign during development. They diverged into bike and squad cruisers. In the final production Hellions are not seen used by civilians and no flame print models appear in the game.