The Acheron Queen

She's the Empress and Mother of all Xenos. She gives birth to Millions of Them

Vanessa regarding the Acheron Queen

Birth
When the Arachnids Shot the Derelict and Released the Trilobite and Impregnated the Pilot and Emerged from his Chest and Crashed on LV-426. And made a Nest in a Room and Layed Eggs

Discovered by Hadley's Hope
She is Found when Jones confronted Thousands of Xenomorph Eggs. The Team found the Eggs and Released a Bunch of Facehuggers and Impregnating them with Alien Embryos. Then saw Dozens of Chestbursters Emerged from them, The First one is Shadow to Emerge from the Impregnated People.

Making a Nest in Hadley's Hope
She moves out of the Derelict with her Warriors and Made a Nest in Hadley's Hope's Heat Room and Impregnated the Heat Engineers with More Face-Huggers and Grew a New Ovirpositor and continued Laying more Eggs and Her Warriors Collected more Colonists and Mobilzing them to become hosts to more Face-Huggers. And she Layed More eggs

7 Years Later
7 Years After the Acheron Queen made a Large Hive in Hadley's Hope. She is Running out of Hosts for her Eggs so She Would have to Move to Earth with her Children