Vault Dalek

The Vault Daleks (or Crucible Daleks) were a subset of bronze Daleks unique to the New Dalek Empire possessing a specialised manipulator arm. They were charged with guarding their creator Davros in the Vault, a special chamber within their giant space station the Crucible.

Profile
Like every individual Dalek of the New Dalek Empire, the Vault Daleks were created from a single cell of Davros' body. However, they differed from the other New Daleks on account of their special type of manipulator arm: a claw manipulator possessing eight pincers, to access special hardware within the Vault. They were tasked by the New Empire's leader, the Supreme Dalek, to keep watch over their creator Davros inside the Vault. (TV: The Stolen Earth/Journey's End)

History
When the Children of Time were transmatted into the Vault, the Vault Daleks held them prisoner until the Reality bomb detonated. When The Doctor's TARDIS materialised and the Meta-Crisis Doctor emerged with a Z-Neutrino Biological Inversion Catalyser, Davros managed to disarm him. Shortly afterwards, Davros disarmed Donna Noble before ordering one of the Vault Daleks to destroy the weapon.

Davros' blast on Donna stimulated the Doctor's DNA that had been transferred to her in the Human-Time Lord Meta-Crisis, her newfound knowledge, combined with human ingenuity, allowing her to disable the reality bomb. Davros quickly set the Vault Daleks on Donna only for her to disable their gunsticks and manipulator arms. When the Vault Daleks tried to physically force her away from the controls, Donna overrode their motive units. When Dalek Caan convinced the Meta-Crisis Doctor to destroy the New Dalek Empire, the Doctor caused a backfire throughout the empire's power feeds, destroying the Vault Daleks along with the rest of the New Dalek Empire. (TV: Journey's End)

Behind the scenes

 * Vault Daleks were not named during The Stolen Earth/Journey's End, but are referred to as such on the official BBC website.
 * They have also become known as "Crucible Daleks", primarily due to the toy manufacturer Character Options naming the variant in this manner as part of its range of Doctor Who 5 inch action figures.