Rachni Queen

Rachni Queens are the matriarchs of the hive-minded rachni. The largest of their species at around twenty feet long, queens are powerful and intelligent creatures who guide the soldiers and workers of their brood with a form of telepathic song, hinting that they also have biotic talent. This allows them to speak through 'receptive' beings, like asari commandos.

Queens resemble brood warriors but are much larger, with darker skin and glowing eyes. They carry the genetic memory of their mothers and are said to be able to lay an egg every few hours, resulting in an entire rachni nest within days. Though queens are usually mated to brood warriors, the reproductive processes of the rachni do not necessarily require a male counterpart. Queens carry the genetic information of their fathers inside them, allowing them to lay eggs even if no brood warriors are present.

Rachni queens live in nests deep underground, often on planets with harsh environments. This presented a problem for the Citadel Council during the Rachni Wars. As the rachni combatants were only soldiers carrying out the orders of their queens, and at the time no Citadel race could survive the hostile rachni homeworlds to communicate with the queens, it was not possible to negotiate with the rachni. When the krogan entered the fray, they were able to infiltrate the rachni nests and kill the queens on every homeworld, hunting the rachni to total extinction.

However, a rachni vessel had been left adrift with many eggs in cryogenic suspension. A corporation called Binary Helix found the vessel and brought an egg to Noveria to hatch it, planning to clone the rachni inside to mass-produce an army, but instead they found a surviving rachni queen. She began to lay eggs, which Binary Helix removed from her presence, only to discover that rachni must develop close to a queen to allow her mind to shape theirs and soothe them. Without the queen, the rachni went rogue and escaped, infiltrating Peak 15.

Matriarch Benezia, on the orders of Saren Arterius, wanted to use the rachni to hunt Saren's enemies, but Benezia needed more from this queen than her eggs. Using her biotics, Benezia took the co-ordinates for the Mu Relay from the rachni queen's mind, drawing on the rachni's genetic memory. When Commander Shepard arrived and defeated Benezia, the queen seized the opportunity to appeal to Shepard, using one of Benezia's commandos to translate. Wanting only to rebuild her species peacefully, the queen humbly asked what Shepard would do - kill her, or allow her to go free. If freed, she escaped into the wilds of Noveria.