The "Lead Alien" was a Cloned Xenomorph born on board the USM Auriga. The Lead Alien was responsible for initiating the Xenomorph outbreak aboard the ship, and was also the Cloned Queen's most loyal and valued servant. It was eventually killed when the Auriga crashed into Earth and exploded.
The Lead Alien was one of 20 Xenomorphs initially bred by Dr. Wren's science team on board the Auriga in 2381. It spent its development and early life in captivity, housed in a cell with two of its brethren, under the close supervision and study of Wren's scientists; Dr. Gediman in particular took a great interest in the Lead Alien's development. During one encounter with Gediman, the Alien quickly learned that insubordination would result in the use of a freezing liquid nitrogen deterrent spray inside the chamber when it was held.
When Gediman and Dr. Williamson were distracted from observing the Xenomorphs by events with the crew of the Betty in the ship's recreation hall, the Lead Alien and one of the others in the holding cell with it turned on the smaller of the three Xenomorphs, savagely attacking it and disembowelling it. The dead creature's acid blood ate through the floor of the holding cell before the scientists could react, and by the time Gediman managed to activate the nitrogen spray the two Xenomorphs had already escaped. Gediman cautiously investigated, and became the first human captive of the Genetic Xenomorphs when the Lead Alien dragged him away to the ship's lower decks. The two escape Xenomorphs quickly smashed open the other cages on the ship and released their fellow Drones and the Cloned Queen.
Later, an armed Dr. Clauss entered the empty holding chamber to investigate. The Lead Alien patiently watched from outside as Clauss entered the cell and then intentionally activated the nitrogen spray, freezing the scientist alive and killing him.
Serving the Queen
The Lead Alien was later selected by the Genetic Queen to bring Ripley 8, who had been captured by the Xenomorphs, to her chamber in the waste tank at the bottom of the ship. After the Newborn killed the Queen, the Hive was left leaderless, and with no humans left alive on board the Auriga after the Betty escaped, the remaining Xenomorphs prepared to enter hibernation until the situation changed. However, soon afterwards, the Auriga crashed into Earth and exploded, killing the Lead Alien and all of the remaining Xenomorphs on board.
Due to the unintentional genetic crossing incurred during the cloning procedure that created the Genetic Xenomorphs, the Lead Alien inherited memories of Ellen Ripley's former life. The Lead Alien also possessed heightened intelligence — most obviously displayed when it deduced a means by which it could escape captivity — and significant patience — it waited until the human personnel observing it were distracted before carrying out its plan to escape, and also observed Clauss entering the cell from which it had fled, waiting until its prey had no hope of escape before activating the nitrogen spray and killing him.
- Several sections of Alien Resurrection's novelization are written from the Lead Alien's perspective, providing insight into the creature's impulses, desires and thought processes.