Emperor Ing

The Emperor Ing is the eldest and strongest of the Ing Horde. It resides in the Sky Temple, within its own Sanctum. Samus Aran's battle with this evil monstrosity is depicted in Metroid Prime 2: Echoes. Being the very first Ing born from Dark Aether's creation, the Emperor Ing has been mutated and strengthened by Phazon energy and the stolen Light of Aether. It has the capability of manipulating both dark and light energy to create attacks that can eat away Energy Tanks of Samus' health in seconds. It is believed to be the guardian of Aether's Leviathan.

First phase
In its first form, the Emperor Ing resembles an overgrown Inglet with Hunter Ing tentacles. Samus can scan the Emperor's Body, Head, and Eye separately. To defeat the Emperor's first form, Samus must find a way to expose the creature's eye, which is its only vulnerable weakpoint. In order to bring down the Emperor's defenses, Samus must first deal with its tentacles, which it uses to attack Samus in various ways. The Emperor will try to whip Samus into the Phazon that lines the arena where it is fought, by swinging its tentacles around. The Emperor can use its tentacles to charge up and launch powerful energy spheres at Samus. It can also create miniature portals, through which it jabs its tentacles in an attempt to impale her. However, destroying a tentacle often leaves behind a power-up.

After Samus causes the Emperor to retract all of its tentacles, the creature's eye, which can be scanned separately from the rest of its body, will be temporarily exposed. The eye has two protective hemispheres rotating around it, and Samus must fire through the narrow break between them. Samus must lock onto and maneuver around the eye, as the protective hemispheres rotate around it constantly, alternating their direction erratically.

While its eye is exposed, the Emperor can fire a powerful laser from it, which can stun Samus and prevent her from shooting. This particular part of the battle is reminiscent of Spore Spawn from Super Metroid, where the boss's weakpoint is exposed for only a brief period of time. Eventually, the Emperor Ing will regenerate a protective covering for the eye, and sprout new tentacles. Throughout the battle, the Emperor Ing regrows its tentacles in varying numbers, until Samus finally deals enough damage to the Emperor's exposed eye. Any weapon can damage the eye, though the Sonic Boom seems to deal the most damage.

Second phase
In its second phase, the Emperor encases itself in an impermeable, magnetically-charged shell reminiscent of a Luminoth Energy Controller or an Ingclaw. This cocoon-like incarnation of the Emperor is covered in circular vents that immediately begin to expel a poisonous gas at the start of the battle, forcing Samus to scale the cocoon with the Spider Ball in order to avoid the purple fog covering the floor. In this stage, the Emperor is undergoing metamorphosis, and Samus, unable to cause any real damage to the pupating Emperor inside, must destroy the 11 vents on the cocoon. This can only be done by damaging the tentacles that emerge from within the vents as Samus draws near them, a difficult task to accomplish, as the tentacles whip around viciously and can actually dislodge her grip on the cocoon's surface. To make matters worse, Inglets in their liquid forms also emerge from the chrysalis and follow Samus around, often ganging up on her in groups. Samus must employ her Bombs to destroy the tentacles that emerge and fight off the Inglets that relentlessly attack.

The Inglets and tentacles are a blessing in disguise, as destroying these yields bountiful health and ammunition. Samus can use this time to fill up on much-needed health using Power Bombs to destroy multiple nuisances at once. It is possible to delay or speed up the Emperor's pupating process by strategically choosing when to bomb the vents from where tentacles emerge. As Samus destroys more tentacles, the vents begin to release more gas into the room, causing the height of the toxic, purple cloud to fluctuate and making anything beneath it extrememly hard to see. At points, the gas rises to such a high level that only the small area near the cocoon's top is left uncovered. If Samus waits here for the miasma to recede, she will be safe from its damage, but will become easy prey for swarms of Inglet.

Once all 11 tentacles have been destroyed, the shell of the chrysalis breaks open, and the Emperor emerges in a mutated form.

Final phase
In the creature's final form, the Emperor Ing's heart, which has become unstable due to increased exposure to Phazon, and the Light of Aether, is exposed to Samus. The Emperor has become more mobile than its previous forms; in this form, it is more insect/arachnid-like in appearance, bearing resemblance to Warrior Ing and Metroid Prime. The final form of the Emperor is the easiest to damage, but has the most devastating attacks. With a new health bar, the Emperor Ing's only weak spot is its very large heart, located inside a mouth-like opening which it can open and close at will.

When it closes its maw, Emperor Ing can change its heart's polarity to project a variety of beam attacks. While its Heart is orange, it cannot project any attacks, but when it is purple, it can create a powerful beam of shadow energy that freezes on contact and causes heavy damage, and when it is white, it can generate "light holes" that project devastating lasers of pure white energy. To recover health, it can spawn Nightbarbs or a previously un-encountered light-based creature, opposite to Nightbarbs, to consume as fodder. These can be destroyed by a mass area-affecting attack, such as the Sonic Boom, for plenty of pickups.

Emperor Ing can't be damaged when its heart is orange; Samus must find a way to make the Emperor change its heart's polarity, thereby making him vulnerable to one of her weapons. To do this, Samus can attack the Emperor's orange heart with any combination of beams. As direct hits are necessary, however, beams can deplete light and dark energy rather quickly. Super Missiles are the most effective way to force Emperor Ing to change its heart's polarity. Once the Emperor's heart changes polarity, it becomes vulnerable to a beam of the opposite polarity. When the Emperor's heart is white, it is vulnerable to the Dark Beam, and when its heart is purple, it is vulnerable to the Light Beam. The Annihilator Beam can hurt the Emperor in both cases. However, if it takes enough hits, the heart will revert back to orange.

The Emperor Ing's attacks include beam attacks reminiscent of Warrior Ing, and a shockwave-inducing jump move similar to the Jump Guardian encountered in Dark Agon. As Emperor Ing's energy is depleted, it will begin to use a ramming attack, similar to Metroid Prime's. While the ram attack is hard to avoid, it is possible, and if Samus can manage to dodge it, the Emperor will run into a wall; it will stand stunned for a short time, revealing a small hole in its back, which is another viable exposure to its heart.

When the Emperor Ing's energy is depleted, it dies, exploding into purple particles similar to the way in which Dark Samus does when defeated. The creature yields the last Light of Aether for the final Energy Controller. When Samus absorbs it, Dark Aether loses its stability and crumbles.

Trivia

 * The Emperor Ing is the only boss in Metroid Prime 2: Echoes guarding the Light of Aether that does not reward Samus with a power-up after its defeat.
 * Strangely, it is possible to inflict severe damage to the Emperor Ing's final form by colliding into a certain location on the underside of its body when using the Screw Attack. This is best done when Emperor Ing jumps up, in which case Samus can Screw Attack under it if near enough to it
 * Interestingly, if Samus deals the final blow while the heart is purple, the resulting cutscene will show the Emperor dying with a white heart. This is likely because in an optimal battle, when the player can deal maximum damage every time its hearts shifts, the final blow would be to a white-hearted Emperor Ing.
 * The first scan that indicates the Emperor is the Ing's Alpha and Omega, and due to these being the first and last letters of the Greek alphabet, can be taken literally as the Emperor being the Beginning and the End of the Ing. This is very fitting, considering it was the first of the Ing to exist and its defeat at the hands of Samus causes the destruction of its world and the entire race. This could also imply that it is a deity of the Ing, as God in the Christian Bible calls himself the "Alpha and Omega".
 * This is the music heard when battling the first and second forms of Emperor Ing:, and this is the music heard when battling the final form of Emperor Ing:.