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The Ing are a warring, ferocious race of beings native to Dark Aether, and are the arch-nemeses of the Luminoth. After having fought the Luminoth for decades of war, they were on the verge of defeating them, having stolen all but one of their planetary energies, and with all but one of the Luminoth in stasis tubes in the Great Temple. However, after Samus Aran came to Aether, she eliminated their kind by destroying Dark Aether. Since their dark-aligned bodies could not stand Aether's different atmosphere, they were left without a dimension to reside in and collapsed with their dimension.

The Ing fought in Metroid Prime 2: Echoes are mostly warrior Ing, as pictured. They are fought best from Light Crystal globes, or once the Dark Suit and Light Suit are recovered, simply from anywhere. Ing are very large. Two boss variations called the Jump Guardian and Boost Guardian exist. The Light Beam works very well against them.

When Ing are still larvae, they are constantly in danger and travel in swarms to lessen this threat. As such, they grow to be aggressive and hateful of all other living things, making perfect soldiers. Ing Larvae are not common around Dark Aether, and can only be encountered in the Ing Hive, although other swarms probably also exist around other global locations.

The head of the Ing Horde is the Emperor Ing, who resides in the Sky Temple. The Emperor Ing has numerous weapons that he can use in self-defense, although powerful creatures and ten keys guard his abode. The Emperor is the keeper of Dark Aether's primary energy source. The Emperor rules a militaristic society that ranks all Ing based on the functions they can perform. Thus, Ing come in all sorts of types.

Warrior Ing are the basic soldiers of the Horde. They are somewhat powerful, exercising fusion attacks, along with various kinetic offensives and dark energy-based laser blasts. The Warrior Ing can also transform into blobs of black goo that can slide across surfaces and up and down walls. Warrior Ing have only one eye, and are quite vulnerable to Light Beams. When a large amount of warrior ing are found in a single room it most often contains a Sky Temple Key.

The Ing also retain elite to help in destroying specific enemies of the Horde, called Hunter Ing. Hunter Ing are very different in physiology from Warrior Ing, in that they have only four tentacles which intertwine in a mass of wires around a red sphere, which is the body. Hunter Ing cannot use energy-based attacks, but instead whip at enemies with their tentacles and shift in and out of the current timespace, attacking enemies from another dimension. In this form, they can be tracked with the Echo Visor, and are quite difficult to lock on to due to their constant movement and teleportation out of the local timespace. The easiest way to defeat them before getting the Annihilator Beam is to fire normal shots at them. They will turn intangible if you fire a charged shot. Hunter Ing can be found in Torvus Sector, Dark Torvus, and on the Sky Temple Grounds.

When faced with large amounts of enemies, the Horde depends on the Ingstorm, tiny Ing that float in the air as a poisonous gas and kill everything in sight. Luminoth are easily eradicated by Ingstorm, although these small aliens can only be found in the Ing Hive and on the Sky Temple Grounds. The Light Suit can protect Luminoth, and Samus, from Ingstorm, but otherwise, the small creatures cause massive amounts of damage as they chew through otherwise impenetrable armor.

Of course, not all Ing are used as soldiers to attack the Luminoth. Some, like the Inglets, are worker drones who labor for the Horde, carrying around vital materials and essentials for the soldiers. When attacked, Inglets can defend themselves, although their attacks are somewhat pathetic, and they can be destroyed easily. Inglets can, like Warrior Ing, shift into a liquid state and flow around areas. They are easy to destroy by Luminoth, and Samus as well.

During their war against the Luminoth, the Ing would generally attack by forcefully possessing nearby beings, much like the traditional demons can forcefully impose itself upon a host, turning them darker than their normal color scheme and increasing their offensive prowess(creatures were common, but the Ing could also possess machines, though it took some time before they learned how to), with a preferrence for creatures with natural abilities for combat, such as the heavier mechanoids or the Space Pirates' footsoldiers stationed upon Aether. These "Darklings" are stronger then the normal versions, but conversely are weaker against the Light Beam, as they are still Ing. In Metroid Prime 2, there are Ing possessed versions of almost all Light Aether enemies. It is unknown if the Darklings that were on Light Aether were able to survive the destruction of Dark Aether. Their true origin is unknown; however, it can be speculated that when the Leviathan crashed on Dark Aether, the Phaz-Ing traveling on it may have been altered on a molecular level, changing from beings of Phazon to beings of darkness.

In Metroid Prime 3: Corruption, Samus enounters a Phazon-charged variant of the Inglet known as the Phaz-Ing.