First Acheron Queen

"Each one of these things comes from an egg, right? So who's laying these eggs?" "I'm not sure. It must be something we haven't seen yet."

-Ripley and Bishop postulating about the Queen's existence.

The First Acheron Queen is the true main antagonist in the 1986 film Aliens.

Birth and Overruning Hadley's Hope
This Queen came from a batch of eggs in the derelict ship that awakened due to being disturbed by Russ and Anne Jorden whom go to the area beyond the colony to search the area on Company Orders from Burke on Earth. This resulting Russ impregnated by one of the released facehuggers in which forced Anne to took him away and retreating back to the Colony much to their daughter Newt's horror. While their mistake in disturbing the eggs was similar with Ripley and her friends decades prior, the consequence was far catastrophic than the latter: Most of the eggs that stored inside the derelict ship winds up awakened, and the released swarm of facehuggers immediately invade Hadley's hope, impregnated a significant amount of colonists and resulting gestation of an army of Xenomorphs. One of the gestated Xenomorphs molted into the Queen whom immediately take control of the area around Atmosphere Processor and established the hive before have her brethren capturing the surviving colonists. All colonists are being wiped out except Newt whom managed to hiding in the vents.

Second Siege on Hadley's Hope
When a squad of Colonial Marines under the command of Lieutenant Gorman and accompanied by Ripley arrived at Hadley's Hope to investigate, they were almost wiped out by Xenomorph Warriors in an ambush inside the Hive, with the few survivors forced to retreat. The Queen herself remained unseen deep within the Hive, although Ripley and the other survivors later theorized as to her existence, reasoning that something had to have laid the Eggs they saw prior to the ambush.

Just as Burke exposed to planned on using Ripley and Newt as smuggling vessel for Xenomorphs Embryo, Xenomorphs cut the power supply of Hadley's Hope and captured Newt, resulting Ripley decided to infiltrate the Hive and took her back.

First Encounter With Ripley
After saved Newt from a newly hatched facehugger, Ripley and Newt stumbles upon a chamber of Atmosphere Processor full of eggs and the Acheron Queen herself. Facing the Acheron Queen alone and surrounded by Warriors, Ripley 'reasoned' with the creature, threatening to destroy all of her Eggs if she and Newt were attacked. Apparently comprehending this, the Queen signaled her circling Warriors to ignore them. However, when one of the Eggs hatched, Ripley incinerated the nest with her flamethrower and destroyed the Queen's ovipositor with grenades from her Pulse Rifle's grenade launcher before fleeing, wounding her. Enraged, the Queen detached herself from her damaged Egg sac and pursued the fleeing humans.

The Queen utilized an elevator to follow Ripley and Newt to the top floor landing platform, where she cornered them on the landing pad. However, Ripley and Newt managed to escape in the Colonial Marines' dropship Smart Ass that Bishop previously sent to the planet via remote control, which arrived before the Queen could close in. During a hasty escape, the dropship collided with the landing pad and collected debris on one of its landing skids, allowing the Queen to hide somewhere in the ship's landing gear, unbeknownst to those on board. Moments after the dropship left, the Atmosphere Processor went critical, vaporizing the Hive and all but destroying Hadley's Hope.

Demise and Posthumous
Acheron Queen revealed her presence by impalint the android Bishop and tear him into 2, before goes for Newt (possibly to secure her as a host for the beginnings of a new hive or perhaps simply to kill her for revenge). Just then, Ripley showed up and fight her with a power loader. The battle ensued, in which the Queen unexpectedly turned the tide of battle by brought Ripley to the airlock with her. As she was stuck with the power loader that pinned her to the airlock's door, she tries to take her enemy with her as Ripley opened the airlock, expelled to the outer space and pulled by LV-426's gravity, where either re-entry or the fall killed her. But even then she was not entirely defeated, as before her final battle she had smuggled her last surviving egg that would hatch a Super Facehugger that would eventually cause Hick's(presumed) and Newt's death and infect Ripley with another Queen embryo as well as giving birth to more faster, deadly breed of Xenomorph.

Aftermath
Though her hive was destroyed, some of the eggs that kept in derelict ship on the planet revealed to survive the blast, and one of them given birth to another Queen.

Personality and Traits
Like all Xenomorph Queens, she values and protects her brethren like any good mother would, and had no qualm in killing any non-xenomorph lifeforms whether as enemy or merely host for her facehugger children. This however, not above "negotiate" with the Hive intruders had they held her brethren hostage. The instance was shown where sho decided to let Ripley and Newt go after threatened to burn the eggs by demonstrating how her flamethrower works. But unfortunately she ended up decide to destroyed her eggs because one of her eggs unexpectedly hatch, enciting her wrath and immediately give chase on Ripley and Newt.

As a fairly young specimen, the first Queen on Acheron was notably smaller than other examples that have been encountered, as her size appeared to be near half the size of her Antarctic incarnation. Although, she still towered over the Warriors around her and was a formidable physical presence, standing some 15' high. While she spent most of her life attached to her enormous ovipositor and therefore immobile, when separated she was a terrifying aggressor with sufficient strength to prove more than a match against a Caterpillar P-5000 Work Loader.

Trivia

 * The scene where the Queen tear Bishop in half is alluded in Tarkatan Xenomorph's Fatality move called Killer Queen, where it called for its Queen to finish the job by impale the weakened opponent from behind with her tail and tear him/her into half.