Dead Wind Cavern

Dead Wind Cavern is a large cave near Primm Pass, south of the REPCONN Test Site and past Harper's Shack, at the top of a long shallow valley. It is one of the most dangerous places in the base game. The cavern is a deathclaw den: a pack of deathclaws and young deathclaws waits at the entrance, more fill the chambers inside, a deathclaw mother guards a hatchery of eggs, and the legendary deathclaw waits in the final room.

The reward for surviving is Mercy, a unique 40mm grenade machine gun lying beside a dead Brotherhood of Steel paladin in the final room, who also wears T-45d power armor and a helmet and carries a few dozen 40mm grenades. Reaching it means fighting through the whole den, so come at level 25 or higher with your best armor, an anti materiel rifle or heavy weapon, plenty of stimpaks and companions who can take a hit. Stealth and a Stealth Boy can get you surprisingly far if you move slowly.

Do not stumble in here early. The hatchery is also where you collect the pile of deathclaw eggs for Red Lucy's quest Bleed Me Dry. Treat the cavern as an endgame challenge that pays off with experience, deathclaw hands and eggs, and one of the best heavy weapons in the game. The approach from Primm Pass or Harper's Shack is the most direct way in, and saving at the entrance before you commit is strongly recommended.