Hellion

Hellions are mid-armored Grineer units which are equipped with personal jet-packs that allow them to jet-jump across terrain quickly as well as hover high in the air, giving them mobility even greater than that of light units.

These Grineers seem to burst their desert-camo Grakata longer than Lancers. Apart from that, they are also able to fire Missile Barrages when airborne, capable of repeatedly knocking down unwary Tenno. The salvo of rockets will fly in haphazard patterns towards the target's general location, dealing moderate damage per rocket.

Amusingly, if shot down while using them, Hellions' jet-packs will detach upon death of the user, zooming around randomly before colliding with terrain and exploding; be warned that this explosion will harm anyone, including the player(s), caught in the blast.

The jet-packs can also be destroyed by shooting them while the Hellion is still alive, which does remove their flight capability and deals moderate explosive damage to those nearby (including Tennos), although it does no damage to the Hellion itself. The jetpacks are guaranteed to explode upon the death of the Hellion if the above mentioned scenario does not occur.

Hellions can be found on Earth, Saturn, Phobos, and Ceres, with each planet having their own unique appearances for their respective units. The Phobos versions are called Arid Hellions identifiable by their brown desert color scheme, while the Earth versions are Frontier Hellions with their dark green forest colors.

Tactics

 * Hellions' AI strongly prefers flying and firing repeated rocket barrages over shooting from behind cover like most Grineer infantry. As a result, they will repeatedly 'hop' about when in narrow interiors and often get stuck in the corners of ceilings and above doorways. This same behavior makes them deadly in open areas as multiple Hellions will often take off immediately when they see a Tenno moving out into the open.
 * They may fly straight up and hover above the battlefield, launching 1 - 5 volleys of rockets before landing. They will also burst-fire their Grakatas will launching rockets, though they are usually the lesser threat since the Grakata's high recoil causes large spread and Hellions cannot aim their weapon straight down.
 * They may also fly horizontally, quickly shifting from one location to another. They will not fire rockets when doing this, however be wary of getting too close as they will still fire their Grakatas.
 * Hiding out of their line of fire and waiting until they land before attacking them will decrease the chance of them returning to flight and firing rocket barrages, or at least give you more time to kill them before they can hit you.
 * Without their jetpacks, they will behave as regular Lancers, making them far less threatening as they also do not have any grenades to deal significant damage.
 * Hellion rockets have habit of hitting the ground frequently, due to their wavy motion in flight.
 * These rockets are treated similarly to those of Grineer Bombards, having explosions pass through thin walls and small objects.
 * Their explosions can be evaded by either (1) remaining in open flight or (2) outrun them through Maneuvers like wall-running and rolling.
 * Warframe abilities that grant the player temporary invincibility such as Slash Dash can be used to negate the rockets, though this is an expensive way to do so if there are no enemies in the vicinity.
 * The Shadow versions of these created in Shadows of the Dead will use their jet-packs and missile barrage. This makes them extremely valuable and powerful when resurrected, especially in outdoor areas.
 * These shadows also have the blue jetpacks of the standard Hellion, which does not change with the variant summoned. This, however, has no effect on their functionality.
 * Most noticeable with Mag, pulling a group together and killing one Hellion can potentially set off a chain reaction with their jetpacks doing your work for you. Be warned that there is possibility for many jetpacks to explode at once, potentially killing you and your sentinel, especially at close proximity.
 * Beware that in survival missions on Phobos, they appear in large groups often crowded together. Killing one will set off a chain reaction caused by exploding jetpacks. It is advised to keep your distance as you can very easily be killed by a couple of explosions.
 * They can potentially damage themselves with lethal effects with their own missile barrage.
 * Deflection abilities such as Frost's Snow Globe will not protect users from the blast radius of either Hellion rockets or explosions from their jetpacks.

Trivia

 * They were first introduced as a "reward" of the Arid Fear Event in the form of the Arid Hellion.
 * They are the first enemy type that utilizes specialized flight equipment, the second being the Ranger series of space units.
 * Unlike other Grineer units, the "normal" version of the Hellion with standard Grineer coloring was the last to be introduced into the game. The Arid Hellion was the first version introduced, followed by the Frontier version.
 * Unusually, normal Hellions are much rarer than Arid or Frontier Hellions, having relatively lower spawn rates.
 * The Hellion bears a similarity in behavior and equipment to the Reaper from StarCraft II, even sharing the same comical jetpack death effect. Interestingly, there is a unit called the Hellion in the latter game as well, though it bears no similarity.

Bugs

 * There is currently an issue where Hellions can no-clip through ceilings and terrain when they fly, easily noticeable in indoor areas. However, once they cut their jetpacks they will become stuck.  Missile barrages will usually result in the Hellion killing themselves with the blasts when this occurs.
 * When they get ragdolled, their jetpack automatically flies, but after death another jetpack is thrown.
 * Occasionally when split in half while in the air, the Hellion launches two jetpacks instead of one.

Media
Hellion