Dalek Progenitor

The Progenitor device was a technology of Dalek design that was intended to bring about the creation of thousands of new members of their kind. They were programmed to recognize the Time Lord known as The Doctor as its enemy. Hundreds of such machines were created by the Dalek Empire in the past(possibly during The Last Great Time War) but all were lost except for one.

Following a previous dalek invasion that was stopped by the Doctor, a Dalek saucer managed to survive but was severely depleted by its hardships and badly damaged. The crew managed to locate one of the last Progenitor devices, but the machine refused to activate for the Daleks as it did not consider them to be "pure". Thus, a group of Daleks went back in time to World War II where they created an android called Professor Edwin Bracewell who was completely unaware of his true origin. Masquerading as Human-created military robots in the Ironside Project for the United Kingdom for use against the Nazis, these Daleks waited for the Doctor to discover them.

When the Eleventh Doctor arrived, the Daleks pretended to be simple Human weapons which caused the Doctor to become frustrated to the point that he declared them to be Daleks. With the testimonial recorded, the group of Daleks transmitted the recording to the Progenitor which recognized the Doctor and thus accepted the command to create new Dalek kind. Within moments, a new paradigm of Daleks were created who quickly exterminated the imperfect forebears who willingly offered themselves extermination and intended to escape through a time corridor to the future so that they could rebuild. Despite the Doctor's best efforts, the Daleks managed to escape and went about the process of rebuilding their empire. (DW: Victory of the Daleks)

If this was made duing Te Last Great Time War is unkown,not alone who exactly created it,but it may be possible that Davros himself made this device and somewhere after a few encounters with The Doctor Davros managed to hide one somewhere for his Daleks to find.