What was a deathclaw before the bombs?

Deathclaws were originally engineered as replacements for human infantry by a covert US military bio-weapons program before the Great War. They were derived from mixed animal stock and subjected to extensive alterations using the Forced Evolutionary Virus (FEV), transforming them into fast-breeding killing machines. However, their enhanced intelligence and resilience also enabled them to thrive following the nuclear apocalypse.

Secret military experiments bring deathclaws to life

According to records salvaged from the ruins of Fort Strong, deathclaws were developed in the "Pan-Immunity Virion Project" by Doctor Sebastian at the U.S. Army Research Laboratory in 2050. This clandestine program sought to develop bio-engineered weapons capable of rapid deployment across a variety of extreme environments without risk to human soldiers.

Initial experiments involved introducing genes from the Jackson‘s Chameleon into a mix of mammal stock, including dogs and large cats. This produced a horned reptilian biped that was named "deathclaw" in reference to the long claws the size of combat knives that sprouted from its fingers. Further refinement at the Mariposa Military Base improved muscle development, eyesight, and suppressed vestigial traits like a tail.

By 2102, Sebastian had iterated on his original deathclaw experiments to create faster, smarter, and deadlier "deathclaw mark II" variants for battlefield use. Enhanced by FEV exposure, their claws could punch through Enclave power armor and they were smart enough to operate in coordinated packs.

Fact: A fully mature male deathclaw stands over 9 ft tall and weighs roughly 870 lbs, though some variants have been observed at over 1000 lbs.

Escape into the wastes after apocalypse

When the Great War broke out in 2077, many deathclaws were still in development or confined to military facilities. However, during the aftermath of nuclear bombardment many somehow escaped into the ruins of cities or wilderness areas. FEV contamination caused by leaks and bomb blasts triggered even more mutations.

Free to roam and breed in areas dangerously irradiated for humans, deathclaw populations boomed. They grew even larger and more formidable as a apex predator of post-apocalyptic America. Having been engineered for the harshest environments, they are just as comfortable stalking the Capital Wasteland ruins as they are the New Vegas deserts.

Initial survivors reported massive horned creatures prowling urban areas that made feral ghouls seem harmless by comparison. Deathclaw packs flourish wherever ruins, tunnels, or caves provide shelter and prey.

Fun fact: The first report of a New Vegas sighting was from a trader found carved up by the bombed-out REPCONN headquarters.

The Master perfects his death machines

While initial military breeding experiments made deathclaws into weapons of war, it was the Master that perfected them into weapons of terror. When his Unity project was nearing completion, the Master conducted further FEV experiments to enhance deathclaws already changed by radiation. His work boosted their resilience and intelligence, turning them into the perfect instrument of his planned conquest.

The Master‘s deathclaws show more developed problem-solving skills, cunning tactics in hunting and battle, and higher reasoning compared to wild variants. They can be trained to use weapons and tools, though they still fiercely prefer their claws for rending prey. Their lifespans were doubled as well, ensuring ages of loyalty to the Master‘s ambitions.

Deathclaws of this lineage are distinguished by their darker scales and prominent horns. The Master‘s pride was a deathclaw he named Gruthar, granted speech and trained from birth as his personal bodyguard.  

- Excerpt from Gruthar capture Interview, 2162 

So while they were bred for war before nuclear fire bathed America, deathclaws have become so much more in the wastes – the ultimate predators, the apex species in many territories, and living reminders of man‘s hubris in playing creator. Yet perhaps now, in their own terrifying way, they are home.